Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 1 | <title>Changes</title> |
| 2 | |
| 3 | <para>The following chapters document the evolution of the V4L2 API, |
| 4 | errata or extensions. They are also intended to help application and |
| 5 | driver writers to port or update their code.</para> |
| 6 | |
| 7 | <section id="diff-v4l"> |
| 8 | <title>Differences between V4L and V4L2</title> |
| 9 | |
| 10 | <para>The Video For Linux API was first introduced in Linux 2.1 to |
| 11 | unify and replace various TV and radio device related interfaces, |
| 12 | developed independently by driver writers in prior years. Starting |
Mauro Carvalho Chehab | b6dc1ba | 2011-06-25 14:28:08 -0300 | [diff] [blame] | 13 | with Linux 2.5 the much improved V4L2 API replaces the V4L API. |
| 14 | The support for the old V4L calls were removed from Kernel, but the |
| 15 | library <xref linkend="libv4l" /> supports the conversion of a V4L |
| 16 | API system call into a V4L2 one.</para> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 17 | |
| 18 | <section> |
| 19 | <title>Opening and Closing Devices</title> |
| 20 | |
| 21 | <para>For compatibility reasons the character device file names |
Hans Verkuil | f44026d | 2010-08-06 12:52:43 -0300 | [diff] [blame] | 22 | recommended for V4L2 video capture, overlay, radio and raw |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 23 | vbi capture devices did not change from those used by V4L. They are |
| 24 | listed in <xref linkend="devices" /> and below in <xref |
| 25 | linkend="v4l-dev" />.</para> |
| 26 | |
Hans Verkuil | f44026d | 2010-08-06 12:52:43 -0300 | [diff] [blame] | 27 | <para>The teletext devices (minor range 192-223) have been removed in |
| 28 | V4L2 and no longer exist. There is no hardware available anymore for handling |
| 29 | pure teletext. Instead raw or sliced VBI is used.</para> |
| 30 | |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 31 | <para>The V4L <filename>videodev</filename> module automatically |
| 32 | assigns minor numbers to drivers in load order, depending on the |
| 33 | registered device type. We recommend that V4L2 drivers by default |
| 34 | register devices with the same numbers, but the system administrator |
| 35 | can assign arbitrary minor numbers using driver module options. The |
| 36 | major device number remains 81.</para> |
| 37 | |
| 38 | <table id="v4l-dev"> |
| 39 | <title>V4L Device Types, Names and Numbers</title> |
| 40 | <tgroup cols="3"> |
| 41 | <thead> |
| 42 | <row> |
| 43 | <entry>Device Type</entry> |
| 44 | <entry>File Name</entry> |
| 45 | <entry>Minor Numbers</entry> |
| 46 | </row> |
| 47 | </thead> |
| 48 | <tbody valign="top"> |
| 49 | <row> |
| 50 | <entry>Video capture and overlay</entry> |
| 51 | <entry><para><filename>/dev/video</filename> and |
| 52 | <filename>/dev/bttv0</filename><footnote> <para>According to |
| 53 | Documentation/devices.txt these should be symbolic links to |
| 54 | <filename>/dev/video0</filename>. Note the original bttv interface is |
| 55 | not compatible with V4L or V4L2.</para> </footnote>, |
| 56 | <filename>/dev/video0</filename> to |
| 57 | <filename>/dev/video63</filename></para></entry> |
| 58 | <entry>0-63</entry> |
| 59 | </row> |
| 60 | <row> |
| 61 | <entry>Radio receiver</entry> |
| 62 | <entry><para><filename>/dev/radio</filename><footnote> |
| 63 | <para>According to |
| 64 | <filename>Documentation/devices.txt</filename> a symbolic link to |
| 65 | <filename>/dev/radio0</filename>.</para> |
| 66 | </footnote>, <filename>/dev/radio0</filename> to |
| 67 | <filename>/dev/radio63</filename></para></entry> |
| 68 | <entry>64-127</entry> |
| 69 | </row> |
| 70 | <row> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 71 | <entry>Raw VBI capture</entry> |
| 72 | <entry><para><filename>/dev/vbi</filename>, |
| 73 | <filename>/dev/vbi0</filename> to |
| 74 | <filename>/dev/vbi31</filename></para></entry> |
| 75 | <entry>224-255</entry> |
| 76 | </row> |
| 77 | </tbody> |
| 78 | </tgroup> |
| 79 | </table> |
| 80 | |
| 81 | <para>V4L prohibits (or used to prohibit) multiple opens of a |
| 82 | device file. V4L2 drivers <emphasis>may</emphasis> support multiple |
| 83 | opens, see <xref linkend="open" /> for details and consequences.</para> |
| 84 | |
Mauro Carvalho Chehab | b6dc1ba | 2011-06-25 14:28:08 -0300 | [diff] [blame] | 85 | <para>V4L drivers respond to V4L2 ioctls with an &EINVAL;.</para> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 86 | </section> |
| 87 | |
| 88 | <section> |
| 89 | <title>Querying Capabilities</title> |
| 90 | |
| 91 | <para>The V4L <constant>VIDIOCGCAP</constant> ioctl is |
| 92 | equivalent to V4L2's &VIDIOC-QUERYCAP;.</para> |
| 93 | |
| 94 | <para>The <structfield>name</structfield> field in struct |
| 95 | <structname>video_capability</structname> became |
| 96 | <structfield>card</structfield> in &v4l2-capability;, |
| 97 | <structfield>type</structfield> was replaced by |
| 98 | <structfield>capabilities</structfield>. Note V4L2 does not |
| 99 | distinguish between device types like this, better think of basic |
| 100 | video input, video output and radio devices supporting a set of |
| 101 | related functions like video capturing, video overlay and VBI |
| 102 | capturing. See <xref linkend="open" /> for an |
| 103 | introduction.<informaltable> |
| 104 | <tgroup cols="3"> |
| 105 | <thead> |
| 106 | <row> |
| 107 | <entry>struct |
| 108 | <structname>video_capability</structname> |
| 109 | <structfield>type</structfield></entry> |
| 110 | <entry>&v4l2-capability; |
| 111 | <structfield>capabilities</structfield> flags</entry> |
| 112 | <entry>Purpose</entry> |
| 113 | </row> |
| 114 | </thead> |
| 115 | <tbody valign="top"> |
| 116 | <row> |
| 117 | <entry><constant>VID_TYPE_CAPTURE</constant></entry> |
| 118 | <entry><constant>V4L2_CAP_VIDEO_CAPTURE</constant></entry> |
| 119 | <entry>The <link linkend="capture">video |
| 120 | capture</link> interface is supported.</entry> |
| 121 | </row> |
| 122 | <row> |
| 123 | <entry><constant>VID_TYPE_TUNER</constant></entry> |
| 124 | <entry><constant>V4L2_CAP_TUNER</constant></entry> |
| 125 | <entry>The device has a <link linkend="tuner">tuner or |
| 126 | modulator</link>.</entry> |
| 127 | </row> |
| 128 | <row> |
| 129 | <entry><constant>VID_TYPE_TELETEXT</constant></entry> |
| 130 | <entry><constant>V4L2_CAP_VBI_CAPTURE</constant></entry> |
| 131 | <entry>The <link linkend="raw-vbi">raw VBI |
| 132 | capture</link> interface is supported.</entry> |
| 133 | </row> |
| 134 | <row> |
| 135 | <entry><constant>VID_TYPE_OVERLAY</constant></entry> |
| 136 | <entry><constant>V4L2_CAP_VIDEO_OVERLAY</constant></entry> |
| 137 | <entry>The <link linkend="overlay">video |
| 138 | overlay</link> interface is supported.</entry> |
| 139 | </row> |
| 140 | <row> |
| 141 | <entry><constant>VID_TYPE_CHROMAKEY</constant></entry> |
| 142 | <entry><constant>V4L2_FBUF_CAP_CHROMAKEY</constant> in |
| 143 | field <structfield>capability</structfield> of |
| 144 | &v4l2-framebuffer;</entry> |
| 145 | <entry>Whether chromakey overlay is supported. For |
| 146 | more information on overlay see |
| 147 | <xref linkend="overlay" />.</entry> |
| 148 | </row> |
| 149 | <row> |
| 150 | <entry><constant>VID_TYPE_CLIPPING</constant></entry> |
| 151 | <entry><constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> |
| 152 | and <constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant> in field |
| 153 | <structfield>capability</structfield> of &v4l2-framebuffer;</entry> |
| 154 | <entry>Whether clipping the overlaid image is |
| 155 | supported, see <xref linkend="overlay" />.</entry> |
| 156 | </row> |
| 157 | <row> |
| 158 | <entry><constant>VID_TYPE_FRAMERAM</constant></entry> |
| 159 | <entry><constant>V4L2_FBUF_CAP_EXTERNOVERLAY</constant> |
| 160 | <emphasis>not set</emphasis> in field |
| 161 | <structfield>capability</structfield> of &v4l2-framebuffer;</entry> |
| 162 | <entry>Whether overlay overwrites frame buffer memory, |
| 163 | see <xref linkend="overlay" />.</entry> |
| 164 | </row> |
| 165 | <row> |
| 166 | <entry><constant>VID_TYPE_SCALES</constant></entry> |
| 167 | <entry><constant>-</constant></entry> |
| 168 | <entry>This flag indicates if the hardware can scale |
| 169 | images. The V4L2 API implies the scale factor by setting the cropping |
| 170 | dimensions and image size with the &VIDIOC-S-CROP; and &VIDIOC-S-FMT; |
| 171 | ioctl, respectively. The driver returns the closest sizes possible. |
| 172 | For more information on cropping and scaling see <xref |
| 173 | linkend="crop" />.</entry> |
| 174 | </row> |
| 175 | <row> |
| 176 | <entry><constant>VID_TYPE_MONOCHROME</constant></entry> |
| 177 | <entry><constant>-</constant></entry> |
| 178 | <entry>Applications can enumerate the supported image |
| 179 | formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device |
| 180 | supports grey scale capturing only. For more information on image |
| 181 | formats see <xref linkend="pixfmt" />.</entry> |
| 182 | </row> |
| 183 | <row> |
| 184 | <entry><constant>VID_TYPE_SUBCAPTURE</constant></entry> |
| 185 | <entry><constant>-</constant></entry> |
| 186 | <entry>Applications can call the &VIDIOC-G-CROP; ioctl |
| 187 | to determine if the device supports capturing a subsection of the full |
| 188 | picture ("cropping" in V4L2). If not, the ioctl returns the &EINVAL;. |
| 189 | For more information on cropping and scaling see <xref |
| 190 | linkend="crop" />.</entry> |
| 191 | </row> |
| 192 | <row> |
| 193 | <entry><constant>VID_TYPE_MPEG_DECODER</constant></entry> |
| 194 | <entry><constant>-</constant></entry> |
| 195 | <entry>Applications can enumerate the supported image |
| 196 | formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device |
| 197 | supports MPEG streams.</entry> |
| 198 | </row> |
| 199 | <row> |
| 200 | <entry><constant>VID_TYPE_MPEG_ENCODER</constant></entry> |
| 201 | <entry><constant>-</constant></entry> |
| 202 | <entry>See above.</entry> |
| 203 | </row> |
| 204 | <row> |
| 205 | <entry><constant>VID_TYPE_MJPEG_DECODER</constant></entry> |
| 206 | <entry><constant>-</constant></entry> |
| 207 | <entry>See above.</entry> |
| 208 | </row> |
| 209 | <row> |
| 210 | <entry><constant>VID_TYPE_MJPEG_ENCODER</constant></entry> |
| 211 | <entry><constant>-</constant></entry> |
| 212 | <entry>See above.</entry> |
| 213 | </row> |
| 214 | </tbody> |
| 215 | </tgroup> |
| 216 | </informaltable></para> |
| 217 | |
| 218 | <para>The <structfield>audios</structfield> field was replaced |
| 219 | by <structfield>capabilities</structfield> flag |
| 220 | <constant>V4L2_CAP_AUDIO</constant>, indicating |
| 221 | <emphasis>if</emphasis> the device has any audio inputs or outputs. To |
| 222 | determine their number applications can enumerate audio inputs with |
| 223 | the &VIDIOC-G-AUDIO; ioctl. The audio ioctls are described in <xref |
| 224 | linkend="audio" />.</para> |
| 225 | |
| 226 | <para>The <structfield>maxwidth</structfield>, |
| 227 | <structfield>maxheight</structfield>, |
| 228 | <structfield>minwidth</structfield> and |
| 229 | <structfield>minheight</structfield> fields were removed. Calling the |
| 230 | &VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; ioctl with the desired dimensions |
| 231 | returns the closest size possible, taking into account the current |
| 232 | video standard, cropping and scaling limitations.</para> |
| 233 | </section> |
| 234 | |
| 235 | <section> |
| 236 | <title>Video Sources</title> |
| 237 | |
| 238 | <para>V4L provides the <constant>VIDIOCGCHAN</constant> and |
| 239 | <constant>VIDIOCSCHAN</constant> ioctl using struct |
| 240 | <structname>video_channel</structname> to enumerate |
| 241 | the video inputs of a V4L device. The equivalent V4L2 ioctls |
| 242 | are &VIDIOC-ENUMINPUT;, &VIDIOC-G-INPUT; and &VIDIOC-S-INPUT; |
| 243 | using &v4l2-input; as discussed in <xref linkend="video" />.</para> |
| 244 | |
| 245 | <para>The <structfield>channel</structfield> field counting |
| 246 | inputs was renamed to <structfield>index</structfield>, the video |
| 247 | input types were renamed as follows: <informaltable> |
| 248 | <tgroup cols="2"> |
| 249 | <thead> |
| 250 | <row> |
| 251 | <entry>struct <structname>video_channel</structname> |
| 252 | <structfield>type</structfield></entry> |
| 253 | <entry>&v4l2-input; |
| 254 | <structfield>type</structfield></entry> |
| 255 | </row> |
| 256 | </thead> |
| 257 | <tbody valign="top"> |
| 258 | <row> |
| 259 | <entry><constant>VIDEO_TYPE_TV</constant></entry> |
| 260 | <entry><constant>V4L2_INPUT_TYPE_TUNER</constant></entry> |
| 261 | </row> |
| 262 | <row> |
| 263 | <entry><constant>VIDEO_TYPE_CAMERA</constant></entry> |
| 264 | <entry><constant>V4L2_INPUT_TYPE_CAMERA</constant></entry> |
| 265 | </row> |
| 266 | </tbody> |
| 267 | </tgroup> |
| 268 | </informaltable></para> |
| 269 | |
| 270 | <para>Unlike the <structfield>tuners</structfield> field |
| 271 | expressing the number of tuners of this input, V4L2 assumes each video |
| 272 | input is connected to at most one tuner. However a tuner can have more |
| 273 | than one input, &ie; RF connectors, and a device can have multiple |
| 274 | tuners. The index number of the tuner associated with the input, if |
| 275 | any, is stored in field <structfield>tuner</structfield> of |
| 276 | &v4l2-input;. Enumeration of tuners is discussed in <xref |
| 277 | linkend="tuner" />.</para> |
| 278 | |
| 279 | <para>The redundant <constant>VIDEO_VC_TUNER</constant> flag was |
| 280 | dropped. Video inputs associated with a tuner are of type |
| 281 | <constant>V4L2_INPUT_TYPE_TUNER</constant>. The |
| 282 | <constant>VIDEO_VC_AUDIO</constant> flag was replaced by the |
| 283 | <structfield>audioset</structfield> field. V4L2 considers devices with |
| 284 | up to 32 audio inputs. Each set bit in the |
| 285 | <structfield>audioset</structfield> field represents one audio input |
| 286 | this video input combines with. For information about audio inputs and |
| 287 | how to switch between them see <xref linkend="audio" />.</para> |
| 288 | |
| 289 | <para>The <structfield>norm</structfield> field describing the |
| 290 | supported video standards was replaced by |
| 291 | <structfield>std</structfield>. The V4L specification mentions a flag |
| 292 | <constant>VIDEO_VC_NORM</constant> indicating whether the standard can |
| 293 | be changed. This flag was a later addition together with the |
| 294 | <structfield>norm</structfield> field and has been removed in the |
| 295 | meantime. V4L2 has a similar, albeit more comprehensive approach |
| 296 | to video standards, see <xref linkend="standard" /> for more |
| 297 | information.</para> |
| 298 | </section> |
| 299 | |
| 300 | <section> |
| 301 | <title>Tuning</title> |
| 302 | |
| 303 | <para>The V4L <constant>VIDIOCGTUNER</constant> and |
| 304 | <constant>VIDIOCSTUNER</constant> ioctl and struct |
| 305 | <structname>video_tuner</structname> can be used to enumerate the |
| 306 | tuners of a V4L TV or radio device. The equivalent V4L2 ioctls are |
| 307 | &VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; using &v4l2-tuner;. Tuners are |
| 308 | covered in <xref linkend="tuner" />.</para> |
| 309 | |
| 310 | <para>The <structfield>tuner</structfield> field counting tuners |
| 311 | was renamed to <structfield>index</structfield>. The fields |
| 312 | <structfield>name</structfield>, <structfield>rangelow</structfield> |
| 313 | and <structfield>rangehigh</structfield> remained unchanged.</para> |
| 314 | |
| 315 | <para>The <constant>VIDEO_TUNER_PAL</constant>, |
| 316 | <constant>VIDEO_TUNER_NTSC</constant> and |
| 317 | <constant>VIDEO_TUNER_SECAM</constant> flags indicating the supported |
| 318 | video standards were dropped. This information is now contained in the |
| 319 | associated &v4l2-input;. No replacement exists for the |
| 320 | <constant>VIDEO_TUNER_NORM</constant> flag indicating whether the |
| 321 | video standard can be switched. The <structfield>mode</structfield> |
| 322 | field to select a different video standard was replaced by a whole new |
| 323 | set of ioctls and structures described in <xref linkend="standard" />. |
| 324 | Due to its ubiquity it should be mentioned the BTTV driver supports |
| 325 | several standards in addition to the regular |
| 326 | <constant>VIDEO_MODE_PAL</constant> (0), |
| 327 | <constant>VIDEO_MODE_NTSC</constant>, |
| 328 | <constant>VIDEO_MODE_SECAM</constant> and |
| 329 | <constant>VIDEO_MODE_AUTO</constant> (3). Namely N/PAL Argentina, |
| 330 | M/PAL, N/PAL, and NTSC Japan with numbers 3-6 (sic).</para> |
| 331 | |
| 332 | <para>The <constant>VIDEO_TUNER_STEREO_ON</constant> flag |
| 333 | indicating stereo reception became |
| 334 | <constant>V4L2_TUNER_SUB_STEREO</constant> in field |
| 335 | <structfield>rxsubchans</structfield>. This field also permits the |
| 336 | detection of monaural and bilingual audio, see the definition of |
| 337 | &v4l2-tuner; for details. Presently no replacement exists for the |
| 338 | <constant>VIDEO_TUNER_RDS_ON</constant> and |
| 339 | <constant>VIDEO_TUNER_MBS_ON</constant> flags.</para> |
| 340 | |
| 341 | <para> The <constant>VIDEO_TUNER_LOW</constant> flag was renamed |
| 342 | to <constant>V4L2_TUNER_CAP_LOW</constant> in the &v4l2-tuner; |
| 343 | <structfield>capability</structfield> field.</para> |
| 344 | |
| 345 | <para>The <constant>VIDIOCGFREQ</constant> and |
| 346 | <constant>VIDIOCSFREQ</constant> ioctl to change the tuner frequency |
| 347 | where renamed to &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY;. They |
| 348 | take a pointer to a &v4l2-frequency; instead of an unsigned long |
| 349 | integer.</para> |
| 350 | </section> |
| 351 | |
| 352 | <section id="v4l-image-properties"> |
| 353 | <title>Image Properties</title> |
| 354 | |
| 355 | <para>V4L2 has no equivalent of the |
| 356 | <constant>VIDIOCGPICT</constant> and <constant>VIDIOCSPICT</constant> |
| 357 | ioctl and struct <structname>video_picture</structname>. The following |
| 358 | fields where replaced by V4L2 controls accessible with the |
| 359 | &VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls:<informaltable> |
| 360 | <tgroup cols="2"> |
| 361 | <thead> |
| 362 | <row> |
| 363 | <entry>struct <structname>video_picture</structname></entry> |
| 364 | <entry>V4L2 Control ID</entry> |
| 365 | </row> |
| 366 | </thead> |
| 367 | <tbody valign="top"> |
| 368 | <row> |
| 369 | <entry><structfield>brightness</structfield></entry> |
| 370 | <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry> |
| 371 | </row> |
| 372 | <row> |
| 373 | <entry><structfield>hue</structfield></entry> |
| 374 | <entry><constant>V4L2_CID_HUE</constant></entry> |
| 375 | </row> |
| 376 | <row> |
| 377 | <entry><structfield>colour</structfield></entry> |
| 378 | <entry><constant>V4L2_CID_SATURATION</constant></entry> |
| 379 | </row> |
| 380 | <row> |
| 381 | <entry><structfield>contrast</structfield></entry> |
| 382 | <entry><constant>V4L2_CID_CONTRAST</constant></entry> |
| 383 | </row> |
| 384 | <row> |
| 385 | <entry><structfield>whiteness</structfield></entry> |
| 386 | <entry><constant>V4L2_CID_WHITENESS</constant></entry> |
| 387 | </row> |
| 388 | </tbody> |
| 389 | </tgroup> |
| 390 | </informaltable></para> |
| 391 | |
| 392 | <para>The V4L picture controls are assumed to range from 0 to |
| 393 | 65535 with no particular reset value. The V4L2 API permits arbitrary |
| 394 | limits and defaults which can be queried with the &VIDIOC-QUERYCTRL; |
| 395 | ioctl. For general information about controls see <xref |
| 396 | linkend="control" />.</para> |
| 397 | |
| 398 | <para>The <structfield>depth</structfield> (average number of |
| 399 | bits per pixel) of a video image is implied by the selected image |
Masanari Iida | bb4f2ee | 2014-03-13 00:57:22 +0900 | [diff] [blame] | 400 | format. V4L2 does not explicitly provide such information assuming |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 401 | applications recognizing the format are aware of the image depth and |
| 402 | others need not know. The <structfield>palette</structfield> field |
| 403 | moved into the &v4l2-pix-format;:<informaltable> |
| 404 | <tgroup cols="2"> |
| 405 | <thead> |
| 406 | <row> |
| 407 | <entry>struct <structname>video_picture</structname> |
| 408 | <structfield>palette</structfield></entry> |
| 409 | <entry>&v4l2-pix-format; |
| 410 | <structfield>pixfmt</structfield></entry> |
| 411 | </row> |
| 412 | </thead> |
| 413 | <tbody valign="top"> |
| 414 | <row> |
| 415 | <entry><constant>VIDEO_PALETTE_GREY</constant></entry> |
| 416 | <entry><para><link |
| 417 | linkend="V4L2-PIX-FMT-GREY"><constant>V4L2_PIX_FMT_GREY</constant></link></para></entry> |
| 418 | </row> |
| 419 | <row> |
| 420 | <entry><constant>VIDEO_PALETTE_HI240</constant></entry> |
| 421 | <entry><para><link |
| 422 | linkend="pixfmt-reserved"><constant>V4L2_PIX_FMT_HI240</constant></link><footnote> |
| 423 | <para>This is a custom format used by the BTTV |
| 424 | driver, not one of the V4L2 standard formats.</para> |
| 425 | </footnote></para></entry> |
| 426 | </row> |
| 427 | <row> |
| 428 | <entry><constant>VIDEO_PALETTE_RGB565</constant></entry> |
| 429 | <entry><para><link |
| 430 | linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB565</constant></link></para></entry> |
| 431 | </row> |
| 432 | <row> |
| 433 | <entry><constant>VIDEO_PALETTE_RGB555</constant></entry> |
| 434 | <entry><para><link |
| 435 | linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB555</constant></link></para></entry> |
| 436 | </row> |
| 437 | <row> |
| 438 | <entry><constant>VIDEO_PALETTE_RGB24</constant></entry> |
| 439 | <entry><para><link |
| 440 | linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR24</constant></link></para></entry> |
| 441 | </row> |
| 442 | <row> |
| 443 | <entry><constant>VIDEO_PALETTE_RGB32</constant></entry> |
| 444 | <entry><para><link |
| 445 | linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR32</constant></link><footnote> |
| 446 | <para>Presumably all V4L RGB formats are |
Masanari Iida | 40e4712 | 2012-03-04 23:16:11 +0900 | [diff] [blame] | 447 | little-endian, although some drivers might interpret them according to machine endianness. V4L2 defines little-endian, big-endian and red/blue |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 448 | swapped variants. For details see <xref linkend="pixfmt-rgb" />.</para> |
| 449 | </footnote></para></entry> |
| 450 | </row> |
| 451 | <row> |
| 452 | <entry><constant>VIDEO_PALETTE_YUV422</constant></entry> |
| 453 | <entry><para><link |
| 454 | linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> |
| 455 | </row> |
| 456 | <row> |
| 457 | <entry><para><constant>VIDEO_PALETTE_YUYV</constant><footnote> |
| 458 | <para><constant>VIDEO_PALETTE_YUV422</constant> |
| 459 | and <constant>VIDEO_PALETTE_YUYV</constant> are the same formats. Some |
| 460 | V4L drivers respond to one, some to the other.</para> |
| 461 | </footnote></para></entry> |
| 462 | <entry><para><link |
| 463 | linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> |
| 464 | </row> |
| 465 | <row> |
| 466 | <entry><constant>VIDEO_PALETTE_UYVY</constant></entry> |
| 467 | <entry><para><link |
| 468 | linkend="V4L2-PIX-FMT-UYVY"><constant>V4L2_PIX_FMT_UYVY</constant></link></para></entry> |
| 469 | </row> |
| 470 | <row> |
| 471 | <entry><constant>VIDEO_PALETTE_YUV420</constant></entry> |
| 472 | <entry>None</entry> |
| 473 | </row> |
| 474 | <row> |
| 475 | <entry><constant>VIDEO_PALETTE_YUV411</constant></entry> |
| 476 | <entry><para><link |
| 477 | linkend="V4L2-PIX-FMT-Y41P"><constant>V4L2_PIX_FMT_Y41P</constant></link><footnote> |
| 478 | <para>Not to be confused with |
| 479 | <constant>V4L2_PIX_FMT_YUV411P</constant>, which is a planar |
| 480 | format.</para> </footnote></para></entry> |
| 481 | </row> |
| 482 | <row> |
| 483 | <entry><constant>VIDEO_PALETTE_RAW</constant></entry> |
| 484 | <entry><para>None<footnote> <para>V4L explains this |
| 485 | as: "RAW capture (BT848)"</para> </footnote></para></entry> |
| 486 | </row> |
| 487 | <row> |
| 488 | <entry><constant>VIDEO_PALETTE_YUV422P</constant></entry> |
| 489 | <entry><para><link |
| 490 | linkend="V4L2-PIX-FMT-YUV422P"><constant>V4L2_PIX_FMT_YUV422P</constant></link></para></entry> |
| 491 | </row> |
| 492 | <row> |
| 493 | <entry><constant>VIDEO_PALETTE_YUV411P</constant></entry> |
| 494 | <entry><para><link |
| 495 | linkend="V4L2-PIX-FMT-YUV411P"><constant>V4L2_PIX_FMT_YUV411P</constant></link><footnote> |
| 496 | <para>Not to be confused with |
| 497 | <constant>V4L2_PIX_FMT_Y41P</constant>, which is a packed |
| 498 | format.</para> </footnote></para></entry> |
| 499 | </row> |
| 500 | <row> |
| 501 | <entry><constant>VIDEO_PALETTE_YUV420P</constant></entry> |
| 502 | <entry><para><link |
| 503 | linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link></para></entry> |
| 504 | </row> |
| 505 | <row> |
| 506 | <entry><constant>VIDEO_PALETTE_YUV410P</constant></entry> |
| 507 | <entry><para><link |
| 508 | linkend="V4L2-PIX-FMT-YVU410"><constant>V4L2_PIX_FMT_YVU410</constant></link></para></entry> |
| 509 | </row> |
| 510 | </tbody> |
| 511 | </tgroup> |
| 512 | </informaltable></para> |
| 513 | |
| 514 | <para>V4L2 image formats are defined in <xref |
| 515 | linkend="pixfmt" />. The image format can be selected with the |
| 516 | &VIDIOC-S-FMT; ioctl.</para> |
| 517 | </section> |
| 518 | |
| 519 | <section> |
| 520 | <title>Audio</title> |
| 521 | |
| 522 | <para>The <constant>VIDIOCGAUDIO</constant> and |
| 523 | <constant>VIDIOCSAUDIO</constant> ioctl and struct |
| 524 | <structname>video_audio</structname> are used to enumerate the |
| 525 | audio inputs of a V4L device. The equivalent V4L2 ioctls are |
| 526 | &VIDIOC-G-AUDIO; and &VIDIOC-S-AUDIO; using &v4l2-audio; as |
| 527 | discussed in <xref linkend="audio" />.</para> |
| 528 | |
| 529 | <para>The <structfield>audio</structfield> "channel number" |
| 530 | field counting audio inputs was renamed to |
| 531 | <structfield>index</structfield>.</para> |
| 532 | |
| 533 | <para>On <constant>VIDIOCSAUDIO</constant> the |
| 534 | <structfield>mode</structfield> field selects <emphasis>one</emphasis> |
| 535 | of the <constant>VIDEO_SOUND_MONO</constant>, |
| 536 | <constant>VIDEO_SOUND_STEREO</constant>, |
| 537 | <constant>VIDEO_SOUND_LANG1</constant> or |
| 538 | <constant>VIDEO_SOUND_LANG2</constant> audio demodulation modes. When |
| 539 | the current audio standard is BTSC |
| 540 | <constant>VIDEO_SOUND_LANG2</constant> refers to SAP and |
| 541 | <constant>VIDEO_SOUND_LANG1</constant> is meaningless. Also |
| 542 | undocumented in the V4L specification, there is no way to query the |
| 543 | selected mode. On <constant>VIDIOCGAUDIO</constant> the driver returns |
| 544 | the <emphasis>actually received</emphasis> audio programmes in this |
| 545 | field. In the V4L2 API this information is stored in the &v4l2-tuner; |
| 546 | <structfield>rxsubchans</structfield> and |
| 547 | <structfield>audmode</structfield> fields, respectively. See <xref |
| 548 | linkend="tuner" /> for more information on tuners. Related to audio |
| 549 | modes &v4l2-audio; also reports if this is a mono or stereo |
| 550 | input, regardless if the source is a tuner.</para> |
| 551 | |
| 552 | <para>The following fields where replaced by V4L2 controls |
| 553 | accessible with the &VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and |
| 554 | &VIDIOC-S-CTRL; ioctls:<informaltable> |
| 555 | <tgroup cols="2"> |
| 556 | <thead> |
| 557 | <row> |
| 558 | <entry>struct |
| 559 | <structname>video_audio</structname></entry> |
| 560 | <entry>V4L2 Control ID</entry> |
| 561 | </row> |
| 562 | </thead> |
| 563 | <tbody valign="top"> |
| 564 | <row> |
| 565 | <entry><structfield>volume</structfield></entry> |
| 566 | <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry> |
| 567 | </row> |
| 568 | <row> |
| 569 | <entry><structfield>bass</structfield></entry> |
| 570 | <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry> |
| 571 | </row> |
| 572 | <row> |
| 573 | <entry><structfield>treble</structfield></entry> |
| 574 | <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry> |
| 575 | </row> |
| 576 | <row> |
| 577 | <entry><structfield>balance</structfield></entry> |
| 578 | <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry> |
| 579 | </row> |
| 580 | </tbody> |
| 581 | </tgroup> |
| 582 | </informaltable></para> |
| 583 | |
| 584 | <para>To determine which of these controls are supported by a |
| 585 | driver V4L provides the <structfield>flags</structfield> |
| 586 | <constant>VIDEO_AUDIO_VOLUME</constant>, |
| 587 | <constant>VIDEO_AUDIO_BASS</constant>, |
| 588 | <constant>VIDEO_AUDIO_TREBLE</constant> and |
| 589 | <constant>VIDEO_AUDIO_BALANCE</constant>. In the V4L2 API the |
| 590 | &VIDIOC-QUERYCTRL; ioctl reports if the respective control is |
| 591 | supported. Accordingly the <constant>VIDEO_AUDIO_MUTABLE</constant> |
| 592 | and <constant>VIDEO_AUDIO_MUTE</constant> flags where replaced by the |
| 593 | boolean <constant>V4L2_CID_AUDIO_MUTE</constant> control.</para> |
| 594 | |
| 595 | <para>All V4L2 controls have a <structfield>step</structfield> |
| 596 | attribute replacing the struct <structname>video_audio</structname> |
| 597 | <structfield>step</structfield> field. The V4L audio controls are |
| 598 | assumed to range from 0 to 65535 with no particular reset value. The |
| 599 | V4L2 API permits arbitrary limits and defaults which can be queried |
| 600 | with the &VIDIOC-QUERYCTRL; ioctl. For general information about |
| 601 | controls see <xref linkend="control" />.</para> |
| 602 | </section> |
| 603 | |
| 604 | <section> |
| 605 | <title>Frame Buffer Overlay</title> |
| 606 | |
| 607 | <para>The V4L2 ioctls equivalent to |
| 608 | <constant>VIDIOCGFBUF</constant> and <constant>VIDIOCSFBUF</constant> |
| 609 | are &VIDIOC-G-FBUF; and &VIDIOC-S-FBUF;. The |
| 610 | <structfield>base</structfield> field of struct |
| 611 | <structname>video_buffer</structname> remained unchanged, except V4L2 |
| 612 | defines a flag to indicate non-destructive overlays instead of a |
| 613 | <constant>NULL</constant> pointer. All other fields moved into the |
| 614 | &v4l2-pix-format; <structfield>fmt</structfield> substructure of |
| 615 | &v4l2-framebuffer;. The <structfield>depth</structfield> field was |
| 616 | replaced by <structfield>pixelformat</structfield>. See <xref |
| 617 | linkend="pixfmt-rgb" /> for a list of RGB formats and their |
| 618 | respective color depths.</para> |
| 619 | |
| 620 | <para>Instead of the special ioctls |
| 621 | <constant>VIDIOCGWIN</constant> and <constant>VIDIOCSWIN</constant> |
| 622 | V4L2 uses the general-purpose data format negotiation ioctls |
| 623 | &VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a |
| 624 | &v4l2-format; as argument. Here the <structfield>win</structfield> |
| 625 | member of the <structfield>fmt</structfield> union is used, a |
| 626 | &v4l2-window;.</para> |
| 627 | |
| 628 | <para>The <structfield>x</structfield>, |
| 629 | <structfield>y</structfield>, <structfield>width</structfield> and |
| 630 | <structfield>height</structfield> fields of struct |
| 631 | <structname>video_window</structname> moved into &v4l2-rect; |
| 632 | substructure <structfield>w</structfield> of struct |
| 633 | <structname>v4l2_window</structname>. The |
| 634 | <structfield>chromakey</structfield>, |
| 635 | <structfield>clips</structfield>, and |
| 636 | <structfield>clipcount</structfield> fields remained unchanged. Struct |
| 637 | <structname>video_clip</structname> was renamed to &v4l2-clip;, also |
| 638 | containing a struct <structname>v4l2_rect</structname>, but the |
| 639 | semantics are still the same.</para> |
| 640 | |
| 641 | <para>The <constant>VIDEO_WINDOW_INTERLACE</constant> flag was |
| 642 | dropped. Instead applications must set the |
| 643 | <structfield>field</structfield> field to |
| 644 | <constant>V4L2_FIELD_ANY</constant> or |
| 645 | <constant>V4L2_FIELD_INTERLACED</constant>. The |
| 646 | <constant>VIDEO_WINDOW_CHROMAKEY</constant> flag moved into |
| 647 | &v4l2-framebuffer;, under the new name |
| 648 | <constant>V4L2_FBUF_FLAG_CHROMAKEY</constant>.</para> |
| 649 | |
| 650 | <para>In V4L, storing a bitmap pointer in |
| 651 | <structfield>clips</structfield> and setting |
| 652 | <structfield>clipcount</structfield> to |
| 653 | <constant>VIDEO_CLIP_BITMAP</constant> (-1) requests bitmap |
| 654 | clipping, using a fixed size bitmap of 1024 × 625 bits. Struct |
| 655 | <structname>v4l2_window</structname> has a separate |
| 656 | <structfield>bitmap</structfield> pointer field for this purpose and |
| 657 | the bitmap size is determined by <structfield>w.width</structfield> and |
| 658 | <structfield>w.height</structfield>.</para> |
| 659 | |
| 660 | <para>The <constant>VIDIOCCAPTURE</constant> ioctl to enable or |
| 661 | disable overlay was renamed to &VIDIOC-OVERLAY;.</para> |
| 662 | </section> |
| 663 | |
| 664 | <section> |
| 665 | <title>Cropping</title> |
| 666 | |
| 667 | <para>To capture only a subsection of the full picture V4L |
| 668 | defines the <constant>VIDIOCGCAPTURE</constant> and |
| 669 | <constant>VIDIOCSCAPTURE</constant> ioctls using struct |
| 670 | <structname>video_capture</structname>. The equivalent V4L2 ioctls are |
| 671 | &VIDIOC-G-CROP; and &VIDIOC-S-CROP; using &v4l2-crop;, and the related |
| 672 | &VIDIOC-CROPCAP; ioctl. This is a rather complex matter, see |
| 673 | <xref linkend="crop" /> for details.</para> |
| 674 | |
| 675 | <para>The <structfield>x</structfield>, |
| 676 | <structfield>y</structfield>, <structfield>width</structfield> and |
| 677 | <structfield>height</structfield> fields moved into &v4l2-rect; |
| 678 | substructure <structfield>c</structfield> of struct |
| 679 | <structname>v4l2_crop</structname>. The |
| 680 | <structfield>decimation</structfield> field was dropped. In the V4L2 |
| 681 | API the scaling factor is implied by the size of the cropping |
| 682 | rectangle and the size of the captured or overlaid image.</para> |
| 683 | |
| 684 | <para>The <constant>VIDEO_CAPTURE_ODD</constant> |
| 685 | and <constant>VIDEO_CAPTURE_EVEN</constant> flags to capture only the |
| 686 | odd or even field, respectively, were replaced by |
| 687 | <constant>V4L2_FIELD_TOP</constant> and |
| 688 | <constant>V4L2_FIELD_BOTTOM</constant> in the field named |
| 689 | <structfield>field</structfield> of &v4l2-pix-format; and |
| 690 | &v4l2-window;. These structures are used to select a capture or |
| 691 | overlay format with the &VIDIOC-S-FMT; ioctl.</para> |
| 692 | </section> |
| 693 | |
| 694 | <section> |
| 695 | <title>Reading Images, Memory Mapping</title> |
| 696 | |
| 697 | <section> |
| 698 | <title>Capturing using the read method</title> |
| 699 | |
| 700 | <para>There is no essential difference between reading images |
| 701 | from a V4L or V4L2 device using the &func-read; function, however V4L2 |
| 702 | drivers are not required to support this I/O method. Applications can |
| 703 | determine if the function is available with the &VIDIOC-QUERYCAP; |
| 704 | ioctl. All V4L2 devices exchanging data with applications must support |
| 705 | the &func-select; and &func-poll; functions.</para> |
| 706 | |
| 707 | <para>To select an image format and size, V4L provides the |
| 708 | <constant>VIDIOCSPICT</constant> and <constant>VIDIOCSWIN</constant> |
| 709 | ioctls. V4L2 uses the general-purpose data format negotiation ioctls |
| 710 | &VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a |
| 711 | &v4l2-format; as argument, here the &v4l2-pix-format; named |
| 712 | <structfield>pix</structfield> of its <structfield>fmt</structfield> |
| 713 | union is used.</para> |
| 714 | |
| 715 | <para>For more information about the V4L2 read interface see |
| 716 | <xref linkend="rw" />.</para> |
| 717 | </section> |
| 718 | <section> |
| 719 | <title>Capturing using memory mapping</title> |
| 720 | |
| 721 | <para>Applications can read from V4L devices by mapping |
| 722 | buffers in device memory, or more often just buffers allocated in |
| 723 | DMA-able system memory, into their address space. This avoids the data |
| 724 | copying overhead of the read method. V4L2 supports memory mapping as |
| 725 | well, with a few differences.</para> |
| 726 | |
| 727 | <informaltable> |
| 728 | <tgroup cols="2"> |
| 729 | <thead> |
| 730 | <row> |
| 731 | <entry>V4L</entry> |
| 732 | <entry>V4L2</entry> |
| 733 | </row> |
| 734 | </thead> |
| 735 | <tbody valign="top"> |
| 736 | <row> |
| 737 | <entry></entry> |
| 738 | <entry>The image format must be selected before |
| 739 | buffers are allocated, with the &VIDIOC-S-FMT; ioctl. When no format |
| 740 | is selected the driver may use the last, possibly by another |
| 741 | application requested format.</entry> |
| 742 | </row> |
| 743 | <row> |
| 744 | <entry><para>Applications cannot change the number of |
| 745 | buffers. The it is built into the driver, unless it has a module |
| 746 | option to change the number when the driver module is |
| 747 | loaded.</para></entry> |
| 748 | <entry><para>The &VIDIOC-REQBUFS; ioctl allocates the |
| 749 | desired number of buffers, this is a required step in the initialization |
| 750 | sequence.</para></entry> |
| 751 | </row> |
| 752 | <row> |
| 753 | <entry><para>Drivers map all buffers as one contiguous |
| 754 | range of memory. The <constant>VIDIOCGMBUF</constant> ioctl is |
| 755 | available to query the number of buffers, the offset of each buffer |
| 756 | from the start of the virtual file, and the overall amount of memory |
| 757 | used, which can be used as arguments for the &func-mmap; |
| 758 | function.</para></entry> |
| 759 | <entry><para>Buffers are individually mapped. The |
| 760 | offset and size of each buffer can be determined with the |
| 761 | &VIDIOC-QUERYBUF; ioctl.</para></entry> |
| 762 | </row> |
| 763 | <row> |
| 764 | <entry><para>The <constant>VIDIOCMCAPTURE</constant> |
| 765 | ioctl prepares a buffer for capturing. It also determines the image |
| 766 | format for this buffer. The ioctl returns immediately, eventually with |
| 767 | an &EAGAIN; if no video signal had been detected. When the driver |
| 768 | supports more than one buffer applications can call the ioctl multiple |
| 769 | times and thus have multiple outstanding capture |
| 770 | requests.</para><para>The <constant>VIDIOCSYNC</constant> ioctl |
| 771 | suspends execution until a particular buffer has been |
| 772 | filled.</para></entry> |
| 773 | <entry><para>Drivers maintain an incoming and outgoing |
| 774 | queue. &VIDIOC-QBUF; enqueues any empty buffer into the incoming |
| 775 | queue. Filled buffers are dequeued from the outgoing queue with the |
| 776 | &VIDIOC-DQBUF; ioctl. To wait until filled buffers become available this |
| 777 | function, &func-select; or &func-poll; can be used. The |
| 778 | &VIDIOC-STREAMON; ioctl must be called once after enqueuing one or |
| 779 | more buffers to start capturing. Its counterpart |
| 780 | &VIDIOC-STREAMOFF; stops capturing and dequeues all buffers from both |
| 781 | queues. Applications can query the signal status, if known, with the |
| 782 | &VIDIOC-ENUMINPUT; ioctl.</para></entry> |
| 783 | </row> |
| 784 | </tbody> |
| 785 | </tgroup> |
| 786 | </informaltable> |
| 787 | |
| 788 | <para>For a more in-depth discussion of memory mapping and |
| 789 | examples, see <xref linkend="mmap" />.</para> |
| 790 | </section> |
| 791 | </section> |
| 792 | |
| 793 | <section> |
| 794 | <title>Reading Raw VBI Data</title> |
| 795 | |
| 796 | <para>Originally the V4L API did not specify a raw VBI capture |
| 797 | interface, only the device file <filename>/dev/vbi</filename> was |
| 798 | reserved for this purpose. The only driver supporting this interface |
| 799 | was the BTTV driver, de-facto defining the V4L VBI interface. Reading |
| 800 | from the device yields a raw VBI image with the following |
| 801 | parameters:<informaltable> |
| 802 | <tgroup cols="2"> |
| 803 | <thead> |
| 804 | <row> |
| 805 | <entry>&v4l2-vbi-format;</entry> |
| 806 | <entry>V4L, BTTV driver</entry> |
| 807 | </row> |
| 808 | </thead> |
| 809 | <tbody valign="top"> |
| 810 | <row> |
| 811 | <entry>sampling_rate</entry> |
| 812 | <entry>28636363 Hz NTSC (or any other 525-line |
| 813 | standard); 35468950 Hz PAL and SECAM (625-line standards)</entry> |
| 814 | </row> |
| 815 | <row> |
| 816 | <entry>offset</entry> |
| 817 | <entry>?</entry> |
| 818 | </row> |
| 819 | <row> |
| 820 | <entry>samples_per_line</entry> |
| 821 | <entry>2048</entry> |
| 822 | </row> |
| 823 | <row> |
| 824 | <entry>sample_format</entry> |
| 825 | <entry>V4L2_PIX_FMT_GREY. The last four bytes (a |
Masanari Iida | 40e4712 | 2012-03-04 23:16:11 +0900 | [diff] [blame] | 826 | machine endianness integer) contain a frame counter.</entry> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 827 | </row> |
| 828 | <row> |
| 829 | <entry>start[]</entry> |
| 830 | <entry>10, 273 NTSC; 22, 335 PAL and SECAM</entry> |
| 831 | </row> |
| 832 | <row> |
| 833 | <entry>count[]</entry> |
| 834 | <entry><para>16, 16<footnote><para>Old driver |
| 835 | versions used different values, eventually the custom |
| 836 | <constant>BTTV_VBISIZE</constant> ioctl was added to query the |
| 837 | correct values.</para></footnote></para></entry> |
| 838 | </row> |
| 839 | <row> |
| 840 | <entry>flags</entry> |
| 841 | <entry>0</entry> |
| 842 | </row> |
| 843 | </tbody> |
| 844 | </tgroup> |
| 845 | </informaltable></para> |
| 846 | |
| 847 | <para>Undocumented in the V4L specification, in Linux 2.3 the |
| 848 | <constant>VIDIOCGVBIFMT</constant> and |
| 849 | <constant>VIDIOCSVBIFMT</constant> ioctls using struct |
| 850 | <structname>vbi_format</structname> were added to determine the VBI |
| 851 | image parameters. These ioctls are only partially compatible with the |
| 852 | V4L2 VBI interface specified in <xref linkend="raw-vbi" />.</para> |
| 853 | |
| 854 | <para>An <structfield>offset</structfield> field does not |
| 855 | exist, <structfield>sample_format</structfield> is supposed to be |
| 856 | <constant>VIDEO_PALETTE_RAW</constant>, equivalent to |
| 857 | <constant>V4L2_PIX_FMT_GREY</constant>. The remaining fields are |
| 858 | probably equivalent to &v4l2-vbi-format;.</para> |
| 859 | |
| 860 | <para>Apparently only the Zoran (ZR 36120) driver implements |
| 861 | these ioctls. The semantics differ from those specified for V4L2 in two |
| 862 | ways. The parameters are reset on &func-open; and |
| 863 | <constant>VIDIOCSVBIFMT</constant> always returns an &EINVAL; if the |
| 864 | parameters are invalid.</para> |
| 865 | </section> |
| 866 | |
| 867 | <section> |
| 868 | <title>Miscellaneous</title> |
| 869 | |
| 870 | <para>V4L2 has no equivalent of the |
| 871 | <constant>VIDIOCGUNIT</constant> ioctl. Applications can find the VBI |
| 872 | device associated with a video capture device (or vice versa) by |
| 873 | reopening the device and requesting VBI data. For details see |
| 874 | <xref linkend="open" />.</para> |
| 875 | |
| 876 | <para>No replacement exists for <constant>VIDIOCKEY</constant>, |
| 877 | and the V4L functions for microcode programming. A new interface for |
| 878 | MPEG compression and playback devices is documented in <xref |
| 879 | linkend="extended-controls" />.</para> |
| 880 | </section> |
| 881 | |
| 882 | </section> |
| 883 | |
| 884 | <section id="hist-v4l2"> |
| 885 | <title>Changes of the V4L2 API</title> |
| 886 | |
| 887 | <para>Soon after the V4L API was added to the kernel it was |
| 888 | criticised as too inflexible. In August 1998 Bill Dirks proposed a |
| 889 | number of improvements and began to work on documentation, example |
| 890 | drivers and applications. With the help of other volunteers this |
| 891 | eventually became the V4L2 API, not just an extension but a |
| 892 | replacement for the V4L API. However it took another four years and |
| 893 | two stable kernel releases until the new API was finally accepted for |
| 894 | inclusion into the kernel in its present form.</para> |
| 895 | |
| 896 | <section> |
| 897 | <title>Early Versions</title> |
| 898 | <para>1998-08-20: First version.</para> |
| 899 | |
| 900 | <para>1998-08-27: The &func-select; function was introduced.</para> |
| 901 | |
| 902 | <para>1998-09-10: New video standard interface.</para> |
| 903 | |
| 904 | <para>1998-09-18: The <constant>VIDIOC_NONCAP</constant> ioctl |
| 905 | was replaced by the otherwise meaningless <constant>O_TRUNC</constant> |
| 906 | &func-open; flag, and the aliases <constant>O_NONCAP</constant> and |
| 907 | <constant>O_NOIO</constant> were defined. Applications can set this |
| 908 | flag if they intend to access controls only, as opposed to capture |
| 909 | applications which need exclusive access. The |
| 910 | <constant>VIDEO_STD_XXX</constant> identifiers are now ordinals |
| 911 | instead of flags, and the <function>video_std_construct()</function> |
| 912 | helper function takes id and transmission arguments.</para> |
| 913 | |
| 914 | <para>1998-09-28: Revamped video standard. Made video controls |
| 915 | individually enumerable.</para> |
| 916 | |
| 917 | <para>1998-10-02: The <structfield>id</structfield> field was |
| 918 | removed from struct <structname>video_standard</structname> and the |
| 919 | color subcarrier fields were renamed. The &VIDIOC-QUERYSTD; ioctl was |
| 920 | renamed to &VIDIOC-ENUMSTD;, &VIDIOC-G-INPUT; to &VIDIOC-ENUMINPUT;. A |
| 921 | first draft of the Codec API was released.</para> |
| 922 | |
| 923 | <para>1998-11-08: Many minor changes. Most symbols have been |
| 924 | renamed. Some material changes to &v4l2-capability;.</para> |
| 925 | |
| 926 | <para>1998-11-12: The read/write directon of some ioctls was misdefined.</para> |
| 927 | |
| 928 | <para>1998-11-14: <constant>V4L2_PIX_FMT_RGB24</constant> |
| 929 | changed to <constant>V4L2_PIX_FMT_BGR24</constant>, and |
| 930 | <constant>V4L2_PIX_FMT_RGB32</constant> changed to |
| 931 | <constant>V4L2_PIX_FMT_BGR32</constant>. Audio controls are now |
| 932 | accessible with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls under |
| 933 | names starting with <constant>V4L2_CID_AUDIO</constant>. The |
| 934 | <constant>V4L2_MAJOR</constant> define was removed from |
| 935 | <filename>videodev.h</filename> since it was only used once in the |
| 936 | <filename>videodev</filename> kernel module. The |
| 937 | <constant>YUV422</constant> and <constant>YUV411</constant> planar |
| 938 | image formats were added.</para> |
| 939 | |
| 940 | <para>1998-11-28: A few ioctl symbols changed. Interfaces for codecs and |
| 941 | video output devices were added.</para> |
| 942 | |
| 943 | <para>1999-01-14: A raw VBI capture interface was added.</para> |
| 944 | |
| 945 | <para>1999-01-19: The <constant>VIDIOC_NEXTBUF</constant> ioctl |
| 946 | was removed.</para> |
| 947 | </section> |
| 948 | |
| 949 | <section> |
| 950 | <title>V4L2 Version 0.16 1999-01-31</title> |
| 951 | <para>1999-01-27: There is now one QBUF ioctl, VIDIOC_QWBUF and VIDIOC_QRBUF |
| 952 | are gone. VIDIOC_QBUF takes a v4l2_buffer as a parameter. Added |
| 953 | digital zoom (cropping) controls.</para> |
| 954 | </section> |
| 955 | |
| 956 | <!-- Where's 0.17? mhs couldn't find that videodev.h, perhaps Bill |
| 957 | forgot to bump the version number or never released it. --> |
| 958 | |
| 959 | <section> |
| 960 | <title>V4L2 Version 0.18 1999-03-16</title> |
| 961 | <para>Added a v4l to V4L2 ioctl compatibility layer to |
| 962 | videodev.c. Driver writers, this changes how you implement your ioctl |
| 963 | handler. See the Driver Writer's Guide. Added some more control id |
| 964 | codes.</para> |
| 965 | </section> |
| 966 | |
| 967 | <section> |
| 968 | <title>V4L2 Version 0.19 1999-06-05</title> |
| 969 | <para>1999-03-18: Fill in the category and catname fields of |
| 970 | v4l2_queryctrl objects before passing them to the driver. Required a |
| 971 | minor change to the VIDIOC_QUERYCTRL handlers in the sample |
| 972 | drivers.</para> |
| 973 | <para>1999-03-31: Better compatibility for v4l memory capture |
| 974 | ioctls. Requires changes to drivers to fully support new compatibility |
| 975 | features, see Driver Writer's Guide and v4l2cap.c. Added new control |
| 976 | IDs: V4L2_CID_HFLIP, _VFLIP. Changed V4L2_PIX_FMT_YUV422P to _YUV422P, |
| 977 | and _YUV411P to _YUV411P.</para> |
| 978 | <para>1999-04-04: Added a few more control IDs.</para> |
| 979 | <para>1999-04-07: Added the button control type.</para> |
| 980 | <para>1999-05-02: Fixed a typo in videodev.h, and added the |
| 981 | V4L2_CTRL_FLAG_GRAYED (later V4L2_CTRL_FLAG_GRABBED) flag.</para> |
| 982 | <para>1999-05-20: Definition of VIDIOC_G_CTRL was wrong causing |
| 983 | a malfunction of this ioctl.</para> |
| 984 | <para>1999-06-05: Changed the value of |
| 985 | V4L2_CID_WHITENESS.</para> |
| 986 | </section> |
| 987 | |
| 988 | <section> |
| 989 | <title>V4L2 Version 0.20 (1999-09-10)</title> |
| 990 | |
| 991 | <para>Version 0.20 introduced a number of changes which were |
| 992 | <emphasis>not backward compatible</emphasis> with 0.19 and earlier |
| 993 | versions. Purpose of these changes was to simplify the API, while |
| 994 | making it more extensible and following common Linux driver API |
| 995 | conventions.</para> |
| 996 | |
| 997 | <orderedlist> |
| 998 | <listitem> |
| 999 | <para>Some typos in <constant>V4L2_FMT_FLAG</constant> |
| 1000 | symbols were fixed. &v4l2-clip; was changed for compatibility with |
| 1001 | v4l. (1999-08-30)</para> |
| 1002 | </listitem> |
| 1003 | |
| 1004 | <listitem> |
| 1005 | <para><constant>V4L2_TUNER_SUB_LANG1</constant> was added. |
| 1006 | (1999-09-05)</para> |
| 1007 | </listitem> |
| 1008 | |
| 1009 | <listitem> |
| 1010 | <para>All ioctl() commands that used an integer argument now |
| 1011 | take a pointer to an integer. Where it makes sense, ioctls will return |
| 1012 | the actual new value in the integer pointed to by the argument, a |
| 1013 | common convention in the V4L2 API. The affected ioctls are: |
| 1014 | VIDIOC_PREVIEW, VIDIOC_STREAMON, VIDIOC_STREAMOFF, VIDIOC_S_FREQ, |
| 1015 | VIDIOC_S_INPUT, VIDIOC_S_OUTPUT, VIDIOC_S_EFFECT. For example |
| 1016 | <programlisting> |
| 1017 | err = ioctl (fd, VIDIOC_XXX, V4L2_XXX); |
| 1018 | </programlisting> becomes <programlisting> |
| 1019 | int a = V4L2_XXX; err = ioctl(fd, VIDIOC_XXX, &a); |
| 1020 | </programlisting> |
| 1021 | </para> |
| 1022 | </listitem> |
| 1023 | |
| 1024 | <listitem> |
| 1025 | <para>All the different get- and set-format commands were |
| 1026 | swept into one &VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctl taking a union |
| 1027 | and a type field selecting the union member as parameter. Purpose is to |
| 1028 | simplify the API by eliminating several ioctls and to allow new and |
| 1029 | driver private data streams without adding new ioctls.</para> |
| 1030 | |
| 1031 | <para>This change obsoletes the following ioctls: |
| 1032 | <constant>VIDIOC_S_INFMT</constant>, |
| 1033 | <constant>VIDIOC_G_INFMT</constant>, |
| 1034 | <constant>VIDIOC_S_OUTFMT</constant>, |
| 1035 | <constant>VIDIOC_G_OUTFMT</constant>, |
| 1036 | <constant>VIDIOC_S_VBIFMT</constant> and |
| 1037 | <constant>VIDIOC_G_VBIFMT</constant>. The image format structure |
| 1038 | <structname>v4l2_format</structname> was renamed to &v4l2-pix-format;, |
| 1039 | while &v4l2-format; is now the envelopping structure for all format |
| 1040 | negotiations.</para> |
| 1041 | </listitem> |
| 1042 | |
| 1043 | <listitem> |
| 1044 | <para>Similar to the changes above, the |
| 1045 | <constant>VIDIOC_G_PARM</constant> and |
| 1046 | <constant>VIDIOC_S_PARM</constant> ioctls were merged with |
| 1047 | <constant>VIDIOC_G_OUTPARM</constant> and |
| 1048 | <constant>VIDIOC_S_OUTPARM</constant>. A |
| 1049 | <structfield>type</structfield> field in the new &v4l2-streamparm; |
| 1050 | selects the respective union member.</para> |
| 1051 | |
| 1052 | <para>This change obsoletes the |
| 1053 | <constant>VIDIOC_G_OUTPARM</constant> and |
| 1054 | <constant>VIDIOC_S_OUTPARM</constant> ioctls.</para> |
| 1055 | </listitem> |
| 1056 | |
| 1057 | <listitem> |
| 1058 | <para>Control enumeration was simplified, and two new |
| 1059 | control flags were introduced and one dropped. The |
| 1060 | <structfield>catname</structfield> field was replaced by a |
| 1061 | <structfield>group</structfield> field.</para> |
| 1062 | |
| 1063 | <para>Drivers can now flag unsupported and temporarily |
| 1064 | unavailable controls with <constant>V4L2_CTRL_FLAG_DISABLED</constant> |
| 1065 | and <constant>V4L2_CTRL_FLAG_GRABBED</constant> respectively. The |
| 1066 | <structfield>group</structfield> name indicates a possibly narrower |
| 1067 | classification than the <structfield>category</structfield>. In other |
| 1068 | words, there may be multiple groups within a category. Controls within |
| 1069 | a group would typically be drawn within a group box. Controls in |
| 1070 | different categories might have a greater separation, or may even |
| 1071 | appear in separate windows.</para> |
| 1072 | </listitem> |
| 1073 | |
| 1074 | <listitem> |
| 1075 | <para>The &v4l2-buffer; <structfield>timestamp</structfield> |
| 1076 | was changed to a 64 bit integer, containing the sampling or output |
| 1077 | time of the frame in nanoseconds. Additionally timestamps will be in |
| 1078 | absolute system time, not starting from zero at the beginning of a |
| 1079 | stream. The data type name for timestamps is stamp_t, defined as a |
| 1080 | signed 64-bit integer. Output devices should not send a buffer out |
| 1081 | until the time in the timestamp field has arrived. I would like to |
| 1082 | follow SGI's lead, and adopt a multimedia timestamping system like |
| 1083 | their UST (Unadjusted System Time). See |
Justin P. Mattock | 0ea6e61 | 2010-07-23 20:51:24 -0700 | [diff] [blame] | 1084 | http://web.archive.org/web/*/http://reality.sgi.com |
Sylwester Nawrocki | c6401af | 2011-12-03 08:37:06 -0300 | [diff] [blame] | 1085 | /cpirazzi_engr/lg/time/intro.html. |
Justin P. Mattock | 0ea6e61 | 2010-07-23 20:51:24 -0700 | [diff] [blame] | 1086 | UST uses timestamps that are 64-bit signed integers |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 1087 | (not struct timeval's) and given in nanosecond units. The UST clock |
| 1088 | starts at zero when the system is booted and runs continuously and |
| 1089 | uniformly. It takes a little over 292 years for UST to overflow. There |
| 1090 | is no way to set the UST clock. The regular Linux time-of-day clock |
| 1091 | can be changed periodically, which would cause errors if it were being |
| 1092 | used for timestamping a multimedia stream. A real UST style clock will |
| 1093 | require some support in the kernel that is not there yet. But in |
| 1094 | anticipation, I will change the timestamp field to a 64-bit integer, |
| 1095 | and I will change the v4l2_masterclock_gettime() function (used only |
| 1096 | by drivers) to return a 64-bit integer.</para> |
| 1097 | </listitem> |
| 1098 | |
| 1099 | <listitem> |
| 1100 | <para>A <structfield>sequence</structfield> field was added |
| 1101 | to &v4l2-buffer;. The <structfield>sequence</structfield> field counts |
| 1102 | captured frames, it is ignored by output devices. When a capture |
| 1103 | driver drops a frame, the sequence number of that frame is |
| 1104 | skipped.</para> |
| 1105 | </listitem> |
| 1106 | </orderedlist> |
| 1107 | </section> |
| 1108 | |
| 1109 | <section> |
| 1110 | <title>V4L2 Version 0.20 incremental changes</title> |
| 1111 | <!-- Version number didn't change anymore, reason unknown. --> |
| 1112 | |
| 1113 | <para>1999-12-23: In &v4l2-vbi-format; the |
| 1114 | <structfield>reserved1</structfield> field became |
| 1115 | <structfield>offset</structfield>. Previously drivers were required to |
| 1116 | clear the <structfield>reserved1</structfield> field.</para> |
| 1117 | |
| 1118 | <para>2000-01-13: The |
| 1119 | <constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant> flag was added.</para> |
| 1120 | |
| 1121 | <para>2000-07-31: The <filename>linux/poll.h</filename> header |
| 1122 | is now included by <filename>videodev.h</filename> for compatibility |
| 1123 | with the original <filename>videodev.h</filename> file.</para> |
| 1124 | |
| 1125 | <para>2000-11-20: <constant>V4L2_TYPE_VBI_OUTPUT</constant> and |
| 1126 | <constant>V4L2_PIX_FMT_Y41P</constant> were added.</para> |
| 1127 | |
| 1128 | <para>2000-11-25: <constant>V4L2_TYPE_VBI_INPUT</constant> was |
| 1129 | added.</para> |
| 1130 | |
| 1131 | <para>2000-12-04: A couple typos in symbol names were fixed.</para> |
| 1132 | |
| 1133 | <para>2001-01-18: To avoid namespace conflicts the |
| 1134 | <constant>fourcc</constant> macro defined in the |
| 1135 | <filename>videodev.h</filename> header file was renamed to |
| 1136 | <constant>v4l2_fourcc</constant>.</para> |
| 1137 | |
| 1138 | <para>2001-01-25: A possible driver-level compatibility problem |
| 1139 | between the <filename>videodev.h</filename> file in Linux 2.4.0 and |
| 1140 | the <filename>videodev.h</filename> file included in the |
| 1141 | <filename>videodevX</filename> patch was fixed. Users of an earlier |
| 1142 | version of <filename>videodevX</filename> on Linux 2.4.0 should |
| 1143 | recompile their V4L and V4L2 drivers.</para> |
| 1144 | |
| 1145 | <para>2001-01-26: A possible kernel-level incompatibility |
| 1146 | between the <filename>videodev.h</filename> file in the |
| 1147 | <filename>videodevX</filename> patch and the |
| 1148 | <filename>videodev.h</filename> file in Linux 2.2.x with devfs patches |
| 1149 | applied was fixed.</para> |
| 1150 | |
| 1151 | <para>2001-03-02: Certain V4L ioctls which pass data in both |
| 1152 | direction although they are defined with read-only parameter, did not |
| 1153 | work correctly through the backward compatibility layer. |
| 1154 | [Solution?]</para> |
| 1155 | |
| 1156 | <para>2001-04-13: Big endian 16-bit RGB formats were added.</para> |
| 1157 | |
| 1158 | <para>2001-09-17: New YUV formats and the &VIDIOC-G-FREQUENCY; and |
| 1159 | &VIDIOC-S-FREQUENCY; ioctls were added. (The old |
| 1160 | <constant>VIDIOC_G_FREQ</constant> and |
| 1161 | <constant>VIDIOC_S_FREQ</constant> ioctls did not take multiple tuners |
| 1162 | into account.)</para> |
| 1163 | |
| 1164 | <para>2000-09-18: <constant>V4L2_BUF_TYPE_VBI</constant> was |
| 1165 | added. This may <emphasis>break compatibility</emphasis> as the |
| 1166 | &VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls may fail now if the struct |
| 1167 | <structname>v4l2_fmt</structname> <structfield>type</structfield> |
| 1168 | field does not contain <constant>V4L2_BUF_TYPE_VBI</constant>. In the |
| 1169 | documentation of the &v4l2-vbi-format; |
| 1170 | <structfield>offset</structfield> field the ambiguous phrase "rising |
| 1171 | edge" was changed to "leading edge".</para> |
| 1172 | </section> |
| 1173 | |
| 1174 | <section> |
| 1175 | <title>V4L2 Version 0.20 2000-11-23</title> |
| 1176 | |
| 1177 | <para>A number of changes were made to the raw VBI |
| 1178 | interface.</para> |
| 1179 | |
| 1180 | <orderedlist> |
| 1181 | <listitem> |
| 1182 | <para>Figures clarifying the line numbering scheme were |
| 1183 | added to the V4L2 API specification. The |
| 1184 | <structfield>start</structfield>[0] and |
| 1185 | <structfield>start</structfield>[1] fields no longer count line |
| 1186 | numbers beginning at zero. Rationale: a) The previous definition was |
| 1187 | unclear. b) The <structfield>start</structfield>[] values are ordinal |
| 1188 | numbers. c) There is no point in inventing a new line numbering |
| 1189 | scheme. We now use line number as defined by ITU-R, period. |
| 1190 | Compatibility: Add one to the start values. Applications depending on |
| 1191 | the previous semantics may not function correctly.</para> |
| 1192 | </listitem> |
| 1193 | |
| 1194 | <listitem> |
| 1195 | <para>The restriction "count[0] > 0 and count[1] > 0" |
| 1196 | has been relaxed to "(count[0] + count[1]) > 0". Rationale: |
| 1197 | Drivers may allocate resources at scan line granularity and some data |
| 1198 | services are transmitted only on the first field. The comment that |
| 1199 | both <structfield>count</structfield> values will usually be equal is |
| 1200 | misleading and pointless and has been removed. This change |
| 1201 | <emphasis>breaks compatibility</emphasis> with earlier versions: |
| 1202 | Drivers may return EINVAL, applications may not function |
| 1203 | correctly.</para> |
| 1204 | </listitem> |
| 1205 | |
| 1206 | <listitem> |
| 1207 | <para>Drivers are again permitted to return negative |
| 1208 | (unknown) start values as proposed earlier. Why this feature was |
| 1209 | dropped is unclear. This change may <emphasis>break |
| 1210 | compatibility</emphasis> with applications depending on the start |
| 1211 | values being positive. The use of <constant>EBUSY</constant> and |
| 1212 | <constant>EINVAL</constant> error codes with the &VIDIOC-S-FMT; ioctl |
| 1213 | was clarified. The &EBUSY; was finally documented, and the |
| 1214 | <structfield>reserved2</structfield> field which was previously |
| 1215 | mentioned only in the <filename>videodev.h</filename> header |
| 1216 | file.</para> |
| 1217 | </listitem> |
| 1218 | |
| 1219 | <listitem> |
| 1220 | <para>New buffer types |
| 1221 | <constant>V4L2_TYPE_VBI_INPUT</constant> and |
| 1222 | <constant>V4L2_TYPE_VBI_OUTPUT</constant> were added. The former is an |
| 1223 | alias for the old <constant>V4L2_TYPE_VBI</constant>, the latter was |
| 1224 | missing in the <filename>videodev.h</filename> file.</para> |
| 1225 | </listitem> |
| 1226 | </orderedlist> |
| 1227 | </section> |
| 1228 | |
| 1229 | <section> |
| 1230 | <title>V4L2 Version 0.20 2002-07-25</title> |
| 1231 | <para>Added sliced VBI interface proposal.</para> |
| 1232 | </section> |
| 1233 | |
| 1234 | <section> |
| 1235 | <title>V4L2 in Linux 2.5.46, 2002-10</title> |
| 1236 | |
| 1237 | <para>Around October-November 2002, prior to an announced |
| 1238 | feature freeze of Linux 2.5, the API was revised, drawing from |
| 1239 | experience with V4L2 0.20. This unnamed version was finally merged |
| 1240 | into Linux 2.5.46.</para> |
| 1241 | |
| 1242 | <orderedlist> |
| 1243 | <listitem> |
| 1244 | <para>As specified in <xref linkend="related" />, drivers |
| 1245 | must make related device functions available under all minor device |
| 1246 | numbers.</para> |
| 1247 | </listitem> |
| 1248 | |
| 1249 | <listitem> |
| 1250 | <para>The &func-open; function requires access mode |
| 1251 | <constant>O_RDWR</constant> regardless of the device type. All V4L2 |
| 1252 | drivers exchanging data with applications must support the |
| 1253 | <constant>O_NONBLOCK</constant> flag. The <constant>O_NOIO</constant> |
| 1254 | flag, a V4L2 symbol which aliased the meaningless |
| 1255 | <constant>O_TRUNC</constant> to indicate accesses without data |
| 1256 | exchange (panel applications) was dropped. Drivers must stay in "panel |
| 1257 | mode" until the application attempts to initiate a data exchange, see |
| 1258 | <xref linkend="open" />.</para> |
| 1259 | </listitem> |
| 1260 | |
| 1261 | <listitem> |
| 1262 | <para>The &v4l2-capability; changed dramatically. Note that |
| 1263 | also the size of the structure changed, which is encoded in the ioctl |
| 1264 | request code, thus older V4L2 devices will respond with an &EINVAL; to |
| 1265 | the new &VIDIOC-QUERYCAP; ioctl.</para> |
| 1266 | |
| 1267 | <para>There are new fields to identify the driver, a new RDS |
| 1268 | device function <constant>V4L2_CAP_RDS_CAPTURE</constant>, the |
| 1269 | <constant>V4L2_CAP_AUDIO</constant> flag indicates if the device has |
| 1270 | any audio connectors, another I/O capability |
| 1271 | <constant>V4L2_CAP_ASYNCIO</constant> can be flagged. In response to |
| 1272 | these changes the <structfield>type</structfield> field became a bit |
| 1273 | set and was merged into the <structfield>flags</structfield> field. |
| 1274 | <constant>V4L2_FLAG_TUNER</constant> was renamed to |
| 1275 | <constant>V4L2_CAP_TUNER</constant>, |
| 1276 | <constant>V4L2_CAP_VIDEO_OVERLAY</constant> replaced |
| 1277 | <constant>V4L2_FLAG_PREVIEW</constant> and |
| 1278 | <constant>V4L2_CAP_VBI_CAPTURE</constant> and |
| 1279 | <constant>V4L2_CAP_VBI_OUTPUT</constant> replaced |
| 1280 | <constant>V4L2_FLAG_DATA_SERVICE</constant>. |
| 1281 | <constant>V4L2_FLAG_READ</constant> and |
| 1282 | <constant>V4L2_FLAG_WRITE</constant> were merged into |
| 1283 | <constant>V4L2_CAP_READWRITE</constant>.</para> |
| 1284 | |
| 1285 | <para>The redundant fields |
| 1286 | <structfield>inputs</structfield>, <structfield>outputs</structfield> |
| 1287 | and <structfield>audios</structfield> were removed. These properties |
| 1288 | can be determined as described in <xref linkend="video" /> and <xref |
| 1289 | linkend="audio" />.</para> |
| 1290 | |
| 1291 | <para>The somewhat volatile and therefore barely useful |
| 1292 | fields <structfield>maxwidth</structfield>, |
| 1293 | <structfield>maxheight</structfield>, |
| 1294 | <structfield>minwidth</structfield>, |
| 1295 | <structfield>minheight</structfield>, |
| 1296 | <structfield>maxframerate</structfield> were removed. This information |
| 1297 | is available as described in <xref linkend="format" /> and |
| 1298 | <xref linkend="standard" />.</para> |
| 1299 | |
| 1300 | <para><constant>V4L2_FLAG_SELECT</constant> was removed. We |
| 1301 | believe the select() function is important enough to require support |
| 1302 | of it in all V4L2 drivers exchanging data with applications. The |
| 1303 | redundant <constant>V4L2_FLAG_MONOCHROME</constant> flag was removed, |
| 1304 | this information is available as described in <xref |
| 1305 | linkend="format" />.</para> |
| 1306 | </listitem> |
| 1307 | |
| 1308 | <listitem> |
| 1309 | <para>In &v4l2-input; the |
| 1310 | <structfield>assoc_audio</structfield> field and the |
| 1311 | <structfield>capability</structfield> field and its only flag |
| 1312 | <constant>V4L2_INPUT_CAP_AUDIO</constant> was replaced by the new |
| 1313 | <structfield>audioset</structfield> field. Instead of linking one |
| 1314 | video input to one audio input this field reports all audio inputs |
| 1315 | this video input combines with.</para> |
| 1316 | |
| 1317 | <para>New fields are <structfield>tuner</structfield> |
| 1318 | (reversing the former link from tuners to video inputs), |
| 1319 | <structfield>std</structfield> and |
| 1320 | <structfield>status</structfield>.</para> |
| 1321 | |
| 1322 | <para>Accordingly &v4l2-output; lost its |
| 1323 | <structfield>capability</structfield> and |
| 1324 | <structfield>assoc_audio</structfield> fields. |
| 1325 | <structfield>audioset</structfield>, |
| 1326 | <structfield>modulator</structfield> and |
| 1327 | <structfield>std</structfield> where added instead.</para> |
| 1328 | </listitem> |
| 1329 | |
| 1330 | <listitem> |
| 1331 | <para>The &v4l2-audio; field |
| 1332 | <structfield>audio</structfield> was renamed to |
| 1333 | <structfield>index</structfield>, for consistency with other |
| 1334 | structures. A new capability flag |
| 1335 | <constant>V4L2_AUDCAP_STEREO</constant> was added to indicated if the |
| 1336 | audio input in question supports stereo sound. |
| 1337 | <constant>V4L2_AUDCAP_EFFECTS</constant> and the corresponding |
| 1338 | <constant>V4L2_AUDMODE</constant> flags where removed. This can be |
| 1339 | easily implemented using controls. (However the same applies to AVL |
| 1340 | which is still there.)</para> |
| 1341 | |
| 1342 | <para>Again for consistency the &v4l2-audioout; field |
| 1343 | <structfield>audio</structfield> was renamed to |
| 1344 | <structfield>index</structfield>.</para> |
| 1345 | </listitem> |
| 1346 | |
| 1347 | <listitem> |
| 1348 | <para>The &v4l2-tuner; |
| 1349 | <structfield>input</structfield> field was replaced by an |
| 1350 | <structfield>index</structfield> field, permitting devices with |
| 1351 | multiple tuners. The link between video inputs and tuners is now |
| 1352 | reversed, inputs point to their tuner. The |
| 1353 | <structfield>std</structfield> substructure became a |
| 1354 | simple set (more about this below) and moved into &v4l2-input;. A |
| 1355 | <structfield>type</structfield> field was added.</para> |
| 1356 | |
| 1357 | <para>Accordingly in &v4l2-modulator; the |
| 1358 | <structfield>output</structfield> was replaced by an |
| 1359 | <structfield>index</structfield> field.</para> |
| 1360 | |
| 1361 | <para>In &v4l2-frequency; the |
| 1362 | <structfield>port</structfield> field was replaced by a |
| 1363 | <structfield>tuner</structfield> field containing the respective tuner |
| 1364 | or modulator index number. A tuner <structfield>type</structfield> |
| 1365 | field was added and the <structfield>reserved</structfield> field |
| 1366 | became larger for future extensions (satellite tuners in |
| 1367 | particular).</para> |
| 1368 | </listitem> |
| 1369 | |
| 1370 | <listitem> |
| 1371 | <para>The idea of completely transparent video standards was |
| 1372 | dropped. Experience showed that applications must be able to work with |
| 1373 | video standards beyond presenting the user a menu. Instead of |
| 1374 | enumerating supported standards with an ioctl applications can now |
| 1375 | refer to standards by &v4l2-std-id; and symbols defined in the |
| 1376 | <filename>videodev2.h</filename> header file. For details see <xref |
| 1377 | linkend="standard" />. The &VIDIOC-G-STD; and |
| 1378 | &VIDIOC-S-STD; now take a pointer to this type as argument. |
| 1379 | &VIDIOC-QUERYSTD; was added to autodetect the received standard, if |
| 1380 | the hardware has this capability. In &v4l2-standard; an |
| 1381 | <structfield>index</structfield> field was added for &VIDIOC-ENUMSTD;. |
| 1382 | A &v4l2-std-id; field named <structfield>id</structfield> was added as |
| 1383 | machine readable identifier, also replacing the |
| 1384 | <structfield>transmission</structfield> field. The misleading |
| 1385 | <structfield>framerate</structfield> field was renamed |
| 1386 | to <structfield>frameperiod</structfield>. The now obsolete |
| 1387 | <structfield>colorstandard</structfield> information, originally |
| 1388 | needed to distguish between variations of standards, were |
| 1389 | removed.</para> |
| 1390 | |
| 1391 | <para>Struct <structname>v4l2_enumstd</structname> ceased to |
| 1392 | be. &VIDIOC-ENUMSTD; now takes a pointer to a &v4l2-standard; |
| 1393 | directly. The information which standards are supported by a |
| 1394 | particular video input or output moved into &v4l2-input; and |
| 1395 | &v4l2-output; fields named <structfield>std</structfield>, |
| 1396 | respectively.</para> |
| 1397 | </listitem> |
| 1398 | |
| 1399 | <listitem> |
| 1400 | <para>The &v4l2-queryctrl; fields |
| 1401 | <structfield>category</structfield> and |
| 1402 | <structfield>group</structfield> did not catch on and/or were not |
| 1403 | implemented as expected and therefore removed.</para> |
| 1404 | </listitem> |
| 1405 | |
| 1406 | <listitem> |
| 1407 | <para>The &VIDIOC-TRY-FMT; ioctl was added to negotiate data |
| 1408 | formats as with &VIDIOC-S-FMT;, but without the overhead of |
| 1409 | programming the hardware and regardless of I/O in progress.</para> |
| 1410 | |
| 1411 | <para>In &v4l2-format; the <structfield>fmt</structfield> |
| 1412 | union was extended to contain &v4l2-window;. All image format |
| 1413 | negotiations are now possible with <constant>VIDIOC_G_FMT</constant>, |
| 1414 | <constant>VIDIOC_S_FMT</constant> and |
| 1415 | <constant>VIDIOC_TRY_FMT</constant>; ioctl. The |
| 1416 | <constant>VIDIOC_G_WIN</constant> and |
| 1417 | <constant>VIDIOC_S_WIN</constant> ioctls to prepare for a video |
| 1418 | overlay were removed. The <structfield>type</structfield> field |
| 1419 | changed to type &v4l2-buf-type; and the buffer type names changed as |
| 1420 | follows.<informaltable> |
| 1421 | <tgroup cols="2"> |
| 1422 | <thead> |
| 1423 | <row> |
| 1424 | <entry>Old defines</entry> |
| 1425 | <entry>&v4l2-buf-type;</entry> |
| 1426 | </row> |
| 1427 | </thead> |
| 1428 | <tbody valign="top"> |
| 1429 | <row> |
| 1430 | <entry><constant>V4L2_BUF_TYPE_CAPTURE</constant></entry> |
| 1431 | <entry><constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant></entry> |
| 1432 | </row> |
| 1433 | <row> |
| 1434 | <entry><constant>V4L2_BUF_TYPE_CODECIN</constant></entry> |
| 1435 | <entry>Omitted for now</entry> |
| 1436 | </row> |
| 1437 | <row> |
| 1438 | <entry><constant>V4L2_BUF_TYPE_CODECOUT</constant></entry> |
| 1439 | <entry>Omitted for now</entry> |
| 1440 | </row> |
| 1441 | <row> |
| 1442 | <entry><constant>V4L2_BUF_TYPE_EFFECTSIN</constant></entry> |
| 1443 | <entry>Omitted for now</entry> |
| 1444 | </row> |
| 1445 | <row> |
| 1446 | <entry><constant>V4L2_BUF_TYPE_EFFECTSIN2</constant></entry> |
| 1447 | <entry>Omitted for now</entry> |
| 1448 | </row> |
| 1449 | <row> |
| 1450 | <entry><constant>V4L2_BUF_TYPE_EFFECTSOUT</constant></entry> |
| 1451 | <entry>Omitted for now</entry> |
| 1452 | </row> |
| 1453 | <row> |
| 1454 | <entry><constant>V4L2_BUF_TYPE_VIDEOOUT</constant></entry> |
| 1455 | <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant></entry> |
| 1456 | </row> |
| 1457 | <row> |
| 1458 | <entry><constant>-</constant></entry> |
| 1459 | <entry><constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant></entry> |
| 1460 | </row> |
| 1461 | <row> |
| 1462 | <entry><constant>-</constant></entry> |
| 1463 | <entry><constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant></entry> |
| 1464 | </row> |
| 1465 | <row> |
| 1466 | <entry><constant>-</constant></entry> |
| 1467 | <entry><constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant></entry> |
| 1468 | </row> |
| 1469 | <row> |
| 1470 | <entry><constant>-</constant></entry> |
| 1471 | <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant></entry> |
| 1472 | </row> |
| 1473 | <row> |
| 1474 | <entry><constant>-</constant></entry> |
| 1475 | <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant></entry> |
| 1476 | </row> |
| 1477 | <row> |
| 1478 | <entry><constant>V4L2_BUF_TYPE_PRIVATE_BASE</constant></entry> |
Hans Verkuil | 9495356f | 2012-09-03 10:09:23 -0300 | [diff] [blame] | 1479 | <entry><constant>V4L2_BUF_TYPE_PRIVATE</constant> (but this is deprecated)</entry> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 1480 | </row> |
| 1481 | </tbody> |
| 1482 | </tgroup> |
| 1483 | </informaltable></para> |
| 1484 | </listitem> |
| 1485 | |
| 1486 | <listitem> |
| 1487 | <para>In &v4l2-fmtdesc; a &v4l2-buf-type; field named |
| 1488 | <structfield>type</structfield> was added as in &v4l2-format;. The |
| 1489 | <constant>VIDIOC_ENUM_FBUFFMT</constant> ioctl is no longer needed and |
| 1490 | was removed. These calls can be replaced by &VIDIOC-ENUM-FMT; with |
| 1491 | type <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para> |
| 1492 | </listitem> |
| 1493 | |
| 1494 | <listitem> |
| 1495 | <para>In &v4l2-pix-format; the |
| 1496 | <structfield>depth</structfield> field was removed, assuming |
| 1497 | applications which recognize the format by its four-character-code |
| 1498 | already know the color depth, and others do not care about it. The |
| 1499 | same rationale lead to the removal of the |
| 1500 | <constant>V4L2_FMT_FLAG_COMPRESSED</constant> flag. The |
| 1501 | <constant>V4L2_FMT_FLAG_SWCONVECOMPRESSED</constant> flag was removed |
| 1502 | because drivers are not supposed to convert images in kernel space. A |
| 1503 | user library of conversion functions should be provided instead. The |
| 1504 | <constant>V4L2_FMT_FLAG_BYTESPERLINE</constant> flag was redundant. |
| 1505 | Applications can set the <structfield>bytesperline</structfield> field |
| 1506 | to zero to get a reasonable default. Since the remaining flags were |
| 1507 | replaced as well, the <structfield>flags</structfield> field itself |
| 1508 | was removed.</para> |
| 1509 | <para>The interlace flags were replaced by a &v4l2-field; |
| 1510 | value in a newly added <structfield>field</structfield> |
| 1511 | field.<informaltable> |
| 1512 | <tgroup cols="2"> |
| 1513 | <thead> |
| 1514 | <row> |
| 1515 | <entry>Old flag</entry> |
| 1516 | <entry>&v4l2-field;</entry> |
| 1517 | </row> |
| 1518 | </thead> |
| 1519 | <tbody valign="top"> |
| 1520 | <row> |
| 1521 | <entry><constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant></entry> |
| 1522 | <entry>?</entry> |
| 1523 | </row> |
| 1524 | <row> |
| 1525 | <entry><constant>V4L2_FMT_FLAG_INTERLACED</constant> |
| 1526 | = <constant>V4L2_FMT_FLAG_COMBINED</constant></entry> |
| 1527 | <entry><constant>V4L2_FIELD_INTERLACED</constant></entry> |
| 1528 | </row> |
| 1529 | <row> |
| 1530 | <entry><constant>V4L2_FMT_FLAG_TOPFIELD</constant> |
| 1531 | = <constant>V4L2_FMT_FLAG_ODDFIELD</constant></entry> |
| 1532 | <entry><constant>V4L2_FIELD_TOP</constant></entry> |
| 1533 | </row> |
| 1534 | <row> |
| 1535 | <entry><constant>V4L2_FMT_FLAG_BOTFIELD</constant> |
| 1536 | = <constant>V4L2_FMT_FLAG_EVENFIELD</constant></entry> |
| 1537 | <entry><constant>V4L2_FIELD_BOTTOM</constant></entry> |
| 1538 | </row> |
| 1539 | <row> |
| 1540 | <entry><constant>-</constant></entry> |
| 1541 | <entry><constant>V4L2_FIELD_SEQ_TB</constant></entry> |
| 1542 | </row> |
| 1543 | <row> |
| 1544 | <entry><constant>-</constant></entry> |
| 1545 | <entry><constant>V4L2_FIELD_SEQ_BT</constant></entry> |
| 1546 | </row> |
| 1547 | <row> |
| 1548 | <entry><constant>-</constant></entry> |
| 1549 | <entry><constant>V4L2_FIELD_ALTERNATE</constant></entry> |
| 1550 | </row> |
| 1551 | </tbody> |
| 1552 | </tgroup> |
| 1553 | </informaltable></para> |
| 1554 | |
| 1555 | <para>The color space flags were replaced by a |
| 1556 | &v4l2-colorspace; value in a newly added |
| 1557 | <structfield>colorspace</structfield> field, where one of |
| 1558 | <constant>V4L2_COLORSPACE_SMPTE170M</constant>, |
| 1559 | <constant>V4L2_COLORSPACE_BT878</constant>, |
| 1560 | <constant>V4L2_COLORSPACE_470_SYSTEM_M</constant> or |
| 1561 | <constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant> replaces |
| 1562 | <constant>V4L2_FMT_CS_601YUV</constant>.</para> |
| 1563 | </listitem> |
| 1564 | |
| 1565 | <listitem> |
| 1566 | <para>In &v4l2-requestbuffers; the |
| 1567 | <structfield>type</structfield> field was properly defined as |
| 1568 | &v4l2-buf-type;. Buffer types changed as mentioned above. A new |
| 1569 | <structfield>memory</structfield> field of type &v4l2-memory; was |
| 1570 | added to distinguish between I/O methods using buffers allocated |
| 1571 | by the driver or the application. See <xref linkend="io" /> for |
| 1572 | details.</para> |
| 1573 | </listitem> |
| 1574 | |
| 1575 | <listitem> |
| 1576 | <para>In &v4l2-buffer; the <structfield>type</structfield> |
| 1577 | field was properly defined as &v4l2-buf-type;. Buffer types changed as |
| 1578 | mentioned above. A <structfield>field</structfield> field of type |
| 1579 | &v4l2-field; was added to indicate if a buffer contains a top or |
| 1580 | bottom field. The old field flags were removed. Since no unadjusted |
| 1581 | system time clock was added to the kernel as planned, the |
| 1582 | <structfield>timestamp</structfield> field changed back from type |
| 1583 | stamp_t, an unsigned 64 bit integer expressing the sample time in |
| 1584 | nanoseconds, to struct <structname>timeval</structname>. With the |
| 1585 | addition of a second memory mapping method the |
| 1586 | <structfield>offset</structfield> field moved into union |
| 1587 | <structfield>m</structfield>, and a new |
| 1588 | <structfield>memory</structfield> field of type &v4l2-memory; was |
| 1589 | added to distinguish between I/O methods. See <xref linkend="io" /> |
| 1590 | for details.</para> |
| 1591 | |
| 1592 | <para>The <constant>V4L2_BUF_REQ_CONTIG</constant> |
| 1593 | flag was used by the V4L compatibility layer, after changes to this |
| 1594 | code it was no longer needed. The |
| 1595 | <constant>V4L2_BUF_ATTR_DEVICEMEM</constant> flag would indicate if |
| 1596 | the buffer was indeed allocated in device memory rather than DMA-able |
| 1597 | system memory. It was barely useful and so was removed.</para> |
| 1598 | </listitem> |
| 1599 | |
| 1600 | <listitem> |
| 1601 | <para>In &v4l2-framebuffer; the |
| 1602 | <structfield>base[3]</structfield> array anticipating double- and |
| 1603 | triple-buffering in off-screen video memory, however without defining |
| 1604 | a synchronization mechanism, was replaced by a single pointer. The |
| 1605 | <constant>V4L2_FBUF_CAP_SCALEUP</constant> and |
| 1606 | <constant>V4L2_FBUF_CAP_SCALEDOWN</constant> flags were removed. |
| 1607 | Applications can determine this capability more accurately using the |
| 1608 | new cropping and scaling interface. The |
| 1609 | <constant>V4L2_FBUF_CAP_CLIPPING</constant> flag was replaced by |
| 1610 | <constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> and |
| 1611 | <constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant>.</para> |
| 1612 | </listitem> |
| 1613 | |
| 1614 | <listitem> |
| 1615 | <para>In &v4l2-clip; the <structfield>x</structfield>, |
| 1616 | <structfield>y</structfield>, <structfield>width</structfield> and |
| 1617 | <structfield>height</structfield> field moved into a |
| 1618 | <structfield>c</structfield> substructure of type &v4l2-rect;. The |
| 1619 | <structfield>x</structfield> and <structfield>y</structfield> fields |
| 1620 | were renamed to <structfield>left</structfield> and |
| 1621 | <structfield>top</structfield>, &ie; offsets to a context dependent |
| 1622 | origin.</para> |
| 1623 | </listitem> |
| 1624 | |
| 1625 | <listitem> |
| 1626 | <para>In &v4l2-window; the <structfield>x</structfield>, |
| 1627 | <structfield>y</structfield>, <structfield>width</structfield> and |
| 1628 | <structfield>height</structfield> field moved into a |
| 1629 | <structfield>w</structfield> substructure as above. A |
| 1630 | <structfield>field</structfield> field of type %v4l2-field; was added |
| 1631 | to distinguish between field and frame (interlaced) overlay.</para> |
| 1632 | </listitem> |
| 1633 | |
| 1634 | <listitem> |
| 1635 | <para>The digital zoom interface, including struct |
| 1636 | <structname>v4l2_zoomcap</structname>, struct |
| 1637 | <structname>v4l2_zoom</structname>, |
| 1638 | <constant>V4L2_ZOOM_NONCAP</constant> and |
| 1639 | <constant>V4L2_ZOOM_WHILESTREAMING</constant> was replaced by a new |
| 1640 | cropping and scaling interface. The previously unused struct |
| 1641 | <structname>v4l2_cropcap</structname> and |
| 1642 | <structname>v4l2_crop</structname> where redefined for this purpose. |
| 1643 | See <xref linkend="crop" /> for details.</para> |
| 1644 | </listitem> |
| 1645 | |
| 1646 | <listitem> |
| 1647 | <para>In &v4l2-vbi-format; the |
| 1648 | <structfield>SAMPLE_FORMAT</structfield> field now contains a |
| 1649 | four-character-code as used to identify video image formats and |
| 1650 | <constant>V4L2_PIX_FMT_GREY</constant> replaces the |
| 1651 | <constant>V4L2_VBI_SF_UBYTE</constant> define. The |
| 1652 | <structfield>reserved</structfield> field was extended.</para> |
| 1653 | </listitem> |
| 1654 | |
| 1655 | <listitem> |
| 1656 | <para>In &v4l2-captureparm; the type of the |
| 1657 | <structfield>timeperframe</structfield> field changed from unsigned |
| 1658 | long to &v4l2-fract;. This allows the accurate expression of multiples |
| 1659 | of the NTSC-M frame rate 30000 / 1001. A new field |
| 1660 | <structfield>readbuffers</structfield> was added to control the driver |
| 1661 | behaviour in read I/O mode.</para> |
| 1662 | |
| 1663 | <para>Similar changes were made to &v4l2-outputparm;.</para> |
| 1664 | </listitem> |
| 1665 | |
| 1666 | <listitem> |
| 1667 | <para>The struct <structname>v4l2_performance</structname> |
| 1668 | and <constant>VIDIOC_G_PERF</constant> ioctl were dropped. Except when |
| 1669 | using the <link linkend="rw">read/write I/O method</link>, which is |
| 1670 | limited anyway, this information is already available to |
| 1671 | applications.</para> |
| 1672 | </listitem> |
| 1673 | |
| 1674 | <listitem> |
| 1675 | <para>The example transformation from RGB to YCbCr color |
| 1676 | space in the old V4L2 documentation was inaccurate, this has been |
| 1677 | corrected in <xref linkend="pixfmt" />.<!-- 0.5670G should be |
| 1678 | 0.587, and 127/112 != 255/224 --></para> |
| 1679 | </listitem> |
| 1680 | </orderedlist> |
| 1681 | </section> |
| 1682 | |
| 1683 | <section> |
| 1684 | <title>V4L2 2003-06-19</title> |
| 1685 | |
| 1686 | <orderedlist> |
| 1687 | <listitem> |
| 1688 | <para>A new capability flag |
| 1689 | <constant>V4L2_CAP_RADIO</constant> was added for radio devices. Prior |
| 1690 | to this change radio devices would identify solely by having exactly one |
| 1691 | tuner whose type field reads <constant>V4L2_TUNER_RADIO</constant>.</para> |
| 1692 | </listitem> |
| 1693 | |
| 1694 | <listitem> |
| 1695 | <para>An optional driver access priority mechanism was |
| 1696 | added, see <xref linkend="app-pri" /> for details.</para> |
| 1697 | </listitem> |
| 1698 | |
| 1699 | <listitem> |
| 1700 | <para>The audio input and output interface was found to be |
| 1701 | incomplete.</para> |
| 1702 | <para>Previously the &VIDIOC-G-AUDIO; |
| 1703 | ioctl would enumerate the available audio inputs. An ioctl to |
| 1704 | determine the current audio input, if more than one combines with the |
| 1705 | current video input, did not exist. So |
| 1706 | <constant>VIDIOC_G_AUDIO</constant> was renamed to |
Mauro Carvalho Chehab | a602d52 | 2011-03-01 10:12:36 -0300 | [diff] [blame] | 1707 | <constant>VIDIOC_G_AUDIO_OLD</constant>, this ioctl was removed on |
| 1708 | Kernel 2.6.39. The &VIDIOC-ENUMAUDIO; ioctl was added to enumerate |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 1709 | audio inputs, while &VIDIOC-G-AUDIO; now reports the current audio |
| 1710 | input.</para> |
| 1711 | <para>The same changes were made to &VIDIOC-G-AUDOUT; and |
| 1712 | &VIDIOC-ENUMAUDOUT;.</para> |
| 1713 | <para>Until further the "videodev" module will automatically |
| 1714 | translate between the old and new ioctls, but drivers and applications |
| 1715 | must be updated to successfully compile again.</para> |
| 1716 | </listitem> |
| 1717 | |
| 1718 | <listitem> |
| 1719 | <para>The &VIDIOC-OVERLAY; ioctl was incorrectly defined with |
| 1720 | write-read parameter. It was changed to write-only, while the write-read |
| 1721 | version was renamed to <constant>VIDIOC_OVERLAY_OLD</constant>. The old |
Mauro Carvalho Chehab | a602d52 | 2011-03-01 10:12:36 -0300 | [diff] [blame] | 1722 | ioctl was removed on Kernel 2.6.39. Until further the "videodev" |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 1723 | kernel module will automatically translate to the new version, so drivers |
| 1724 | must be recompiled, but not applications.</para> |
| 1725 | </listitem> |
| 1726 | |
| 1727 | <listitem> |
| 1728 | <para><xref linkend="overlay" /> incorrectly stated that |
| 1729 | clipping rectangles define regions where the video can be seen. |
| 1730 | Correct is that clipping rectangles define regions where |
| 1731 | <emphasis>no</emphasis> video shall be displayed and so the graphics |
| 1732 | surface can be seen.</para> |
| 1733 | </listitem> |
| 1734 | |
| 1735 | <listitem> |
| 1736 | <para>The &VIDIOC-S-PARM; and &VIDIOC-S-CTRL; ioctls were |
| 1737 | defined with write-only parameter, inconsistent with other ioctls |
| 1738 | modifying their argument. They were changed to write-read, while a |
| 1739 | <constant>_OLD</constant> suffix was added to the write-only versions. |
Mauro Carvalho Chehab | a602d52 | 2011-03-01 10:12:36 -0300 | [diff] [blame] | 1740 | The old ioctls were removed on Kernel 2.6.39. Drivers and |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 1741 | applications assuming a constant parameter need an update.</para> |
| 1742 | </listitem> |
| 1743 | </orderedlist> |
| 1744 | </section> |
| 1745 | |
| 1746 | <section> |
| 1747 | <title>V4L2 2003-11-05</title> |
| 1748 | <orderedlist> |
| 1749 | <listitem> |
| 1750 | <para>In <xref linkend="pixfmt-rgb" /> the following pixel |
| 1751 | formats were incorrectly transferred from Bill Dirks' V4L2 |
| 1752 | specification. Descriptions below refer to bytes in memory, in |
| 1753 | ascending address order.<informaltable> |
| 1754 | <tgroup cols="3"> |
| 1755 | <thead> |
| 1756 | <row> |
| 1757 | <entry>Symbol</entry> |
| 1758 | <entry>In this document prior to revision |
| 1759 | 0.5</entry> |
| 1760 | <entry>Corrected</entry> |
| 1761 | </row> |
| 1762 | </thead> |
| 1763 | <tbody valign="top"> |
| 1764 | <row> |
| 1765 | <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> |
| 1766 | <entry>B, G, R</entry> |
| 1767 | <entry>R, G, B</entry> |
| 1768 | </row> |
| 1769 | <row> |
| 1770 | <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> |
| 1771 | <entry>R, G, B</entry> |
| 1772 | <entry>B, G, R</entry> |
| 1773 | </row> |
| 1774 | <row> |
| 1775 | <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> |
| 1776 | <entry>B, G, R, X</entry> |
| 1777 | <entry>R, G, B, X</entry> |
| 1778 | </row> |
| 1779 | <row> |
| 1780 | <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> |
| 1781 | <entry>R, G, B, X</entry> |
| 1782 | <entry>B, G, R, X</entry> |
| 1783 | </row> |
| 1784 | </tbody> |
| 1785 | </tgroup> |
| 1786 | </informaltable> The |
| 1787 | <constant>V4L2_PIX_FMT_BGR24</constant> example was always |
| 1788 | correct.</para> |
| 1789 | <para>In <xref linkend="v4l-image-properties" /> the mapping |
| 1790 | of the V4L <constant>VIDEO_PALETTE_RGB24</constant> and |
| 1791 | <constant>VIDEO_PALETTE_RGB32</constant> formats to V4L2 pixel formats |
| 1792 | was accordingly corrected.</para> |
| 1793 | </listitem> |
| 1794 | |
| 1795 | <listitem> |
| 1796 | <para>Unrelated to the fixes above, drivers may still |
| 1797 | interpret some V4L2 RGB pixel formats differently. These issues have |
| 1798 | yet to be addressed, for details see <xref |
| 1799 | linkend="pixfmt-rgb" />.</para> |
| 1800 | </listitem> |
| 1801 | </orderedlist> |
| 1802 | </section> |
| 1803 | |
| 1804 | <section> |
| 1805 | <title>V4L2 in Linux 2.6.6, 2004-05-09</title> |
| 1806 | <orderedlist> |
| 1807 | <listitem> |
| 1808 | <para>The &VIDIOC-CROPCAP; ioctl was incorrectly defined |
| 1809 | with read-only parameter. It is now defined as write-read ioctl, while |
| 1810 | the read-only version was renamed to |
Mauro Carvalho Chehab | a602d52 | 2011-03-01 10:12:36 -0300 | [diff] [blame] | 1811 | <constant>VIDIOC_CROPCAP_OLD</constant>. The old ioctl was removed |
| 1812 | on Kernel 2.6.39.</para> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 1813 | </listitem> |
| 1814 | </orderedlist> |
| 1815 | </section> |
| 1816 | |
| 1817 | <section> |
| 1818 | <title>V4L2 in Linux 2.6.8</title> |
| 1819 | <orderedlist> |
| 1820 | <listitem> |
| 1821 | <para>A new field <structfield>input</structfield> (former |
| 1822 | <structfield>reserved[0]</structfield>) was added to the &v4l2-buffer; |
| 1823 | structure. Purpose of this field is to alternate between video inputs |
| 1824 | (⪚ cameras) in step with the video capturing process. This function |
| 1825 | must be enabled with the new <constant>V4L2_BUF_FLAG_INPUT</constant> |
| 1826 | flag. The <structfield>flags</structfield> field is no longer |
| 1827 | read-only.</para> |
| 1828 | </listitem> |
| 1829 | </orderedlist> |
| 1830 | </section> |
| 1831 | |
| 1832 | <section> |
| 1833 | <title>V4L2 spec erratum 2004-08-01</title> |
| 1834 | |
| 1835 | <orderedlist> |
| 1836 | <listitem> |
| 1837 | <para>The return value of the |
| 1838 | <xref linkend="func-open" /> function was incorrectly documented.</para> |
| 1839 | </listitem> |
| 1840 | |
| 1841 | <listitem> |
| 1842 | <para>Audio output ioctls end in -AUDOUT, not -AUDIOOUT.</para> |
| 1843 | </listitem> |
| 1844 | |
| 1845 | <listitem> |
| 1846 | <para>In the Current Audio Input example the |
| 1847 | <constant>VIDIOC_G_AUDIO</constant> ioctl took the wrong |
| 1848 | argument.</para> |
| 1849 | </listitem> |
| 1850 | |
| 1851 | <listitem> |
| 1852 | <para>The documentation of the &VIDIOC-QBUF; and |
| 1853 | &VIDIOC-DQBUF; ioctls did not mention the &v4l2-buffer; |
| 1854 | <structfield>memory</structfield> field. It was also missing from |
| 1855 | examples. Also on the <constant>VIDIOC_DQBUF</constant> page the &EIO; |
| 1856 | was not documented.</para> |
| 1857 | </listitem> |
| 1858 | </orderedlist> |
| 1859 | </section> |
| 1860 | |
| 1861 | <section> |
| 1862 | <title>V4L2 in Linux 2.6.14</title> |
| 1863 | <orderedlist> |
| 1864 | <listitem> |
| 1865 | <para>A new sliced VBI interface was added. It is documented |
| 1866 | in <xref linkend="sliced" /> and replaces the interface first |
| 1867 | proposed in V4L2 specification 0.8.</para> |
| 1868 | </listitem> |
| 1869 | </orderedlist> |
| 1870 | </section> |
| 1871 | |
| 1872 | <section> |
| 1873 | <title>V4L2 in Linux 2.6.15</title> |
| 1874 | <orderedlist> |
| 1875 | <listitem> |
| 1876 | <para>The &VIDIOC-LOG-STATUS; ioctl was added.</para> |
| 1877 | </listitem> |
| 1878 | |
| 1879 | <listitem> |
| 1880 | <para>New video standards |
| 1881 | <constant>V4L2_STD_NTSC_443</constant>, |
| 1882 | <constant>V4L2_STD_SECAM_LC</constant>, |
| 1883 | <constant>V4L2_STD_SECAM_DK</constant> (a set of SECAM D, K and K1), |
| 1884 | and <constant>V4L2_STD_ATSC</constant> (a set of |
| 1885 | <constant>V4L2_STD_ATSC_8_VSB</constant> and |
| 1886 | <constant>V4L2_STD_ATSC_16_VSB</constant>) were defined. Note the |
| 1887 | <constant>V4L2_STD_525_60</constant> set now includes |
| 1888 | <constant>V4L2_STD_NTSC_443</constant>. See also <xref |
| 1889 | linkend="v4l2-std-id" />.</para> |
| 1890 | </listitem> |
| 1891 | |
| 1892 | <listitem> |
| 1893 | <para>The <constant>VIDIOC_G_COMP</constant> and |
| 1894 | <constant>VIDIOC_S_COMP</constant> ioctl were renamed to |
| 1895 | <constant>VIDIOC_G_MPEGCOMP</constant> and |
| 1896 | <constant>VIDIOC_S_MPEGCOMP</constant> respectively. Their argument |
| 1897 | was replaced by a struct |
| 1898 | <structname>v4l2_mpeg_compression</structname> pointer. (The |
| 1899 | <constant>VIDIOC_G_MPEGCOMP</constant> and |
| 1900 | <constant>VIDIOC_S_MPEGCOMP</constant> ioctls where removed in Linux |
| 1901 | 2.6.25.)</para> |
| 1902 | </listitem> |
| 1903 | </orderedlist> |
| 1904 | </section> |
| 1905 | |
| 1906 | <section> |
| 1907 | <title>V4L2 spec erratum 2005-11-27</title> |
| 1908 | <para>The capture example in <xref linkend="capture-example" /> |
| 1909 | called the &VIDIOC-S-CROP; ioctl without checking if cropping is |
| 1910 | supported. In the video standard selection example in |
| 1911 | <xref linkend="standard" /> the &VIDIOC-S-STD; call used the wrong |
| 1912 | argument type.</para> |
| 1913 | </section> |
| 1914 | |
| 1915 | <section> |
| 1916 | <title>V4L2 spec erratum 2006-01-10</title> |
| 1917 | <orderedlist> |
| 1918 | <listitem> |
| 1919 | <para>The <constant>V4L2_IN_ST_COLOR_KILL</constant> flag in |
| 1920 | &v4l2-input; not only indicates if the color killer is enabled, but |
| 1921 | also if it is active. (The color killer disables color decoding when |
| 1922 | it detects no color in the video signal to improve the image |
| 1923 | quality.)</para> |
| 1924 | </listitem> |
| 1925 | |
| 1926 | <listitem> |
| 1927 | <para>&VIDIOC-S-PARM; is a write-read ioctl, not write-only as |
| 1928 | stated on its reference page. The ioctl changed in 2003 as noted above.</para> |
| 1929 | </listitem> |
| 1930 | </orderedlist> |
| 1931 | </section> |
| 1932 | |
| 1933 | <section> |
| 1934 | <title>V4L2 spec erratum 2006-02-03</title> |
| 1935 | <orderedlist> |
| 1936 | <listitem> |
| 1937 | <para>In &v4l2-captureparm; and &v4l2-outputparm; the |
| 1938 | <structfield>timeperframe</structfield> field gives the time in |
| 1939 | seconds, not microseconds.</para> |
| 1940 | </listitem> |
| 1941 | </orderedlist> |
| 1942 | </section> |
| 1943 | |
| 1944 | <section> |
| 1945 | <title>V4L2 spec erratum 2006-02-04</title> |
| 1946 | <orderedlist> |
| 1947 | <listitem> |
| 1948 | <para>The <structfield>clips</structfield> field in |
| 1949 | &v4l2-window; must point to an array of &v4l2-clip;, not a linked |
| 1950 | list, because drivers ignore the struct |
| 1951 | <structname>v4l2_clip</structname>.<structfield>next</structfield> |
| 1952 | pointer.</para> |
| 1953 | </listitem> |
| 1954 | </orderedlist> |
| 1955 | </section> |
| 1956 | |
| 1957 | <section> |
| 1958 | <title>V4L2 in Linux 2.6.17</title> |
| 1959 | <orderedlist> |
| 1960 | <listitem> |
| 1961 | <para>New video standard macros were added: |
| 1962 | <constant>V4L2_STD_NTSC_M_KR</constant> (NTSC M South Korea), and the |
| 1963 | sets <constant>V4L2_STD_MN</constant>, |
| 1964 | <constant>V4L2_STD_B</constant>, <constant>V4L2_STD_GH</constant> and |
| 1965 | <constant>V4L2_STD_DK</constant>. The |
| 1966 | <constant>V4L2_STD_NTSC</constant> and |
| 1967 | <constant>V4L2_STD_SECAM</constant> sets now include |
| 1968 | <constant>V4L2_STD_NTSC_M_KR</constant> and |
| 1969 | <constant>V4L2_STD_SECAM_LC</constant> respectively.</para> |
| 1970 | </listitem> |
| 1971 | |
| 1972 | <listitem> |
| 1973 | <para>A new <constant>V4L2_TUNER_MODE_LANG1_LANG2</constant> |
| 1974 | was defined to record both languages of a bilingual program. The |
| 1975 | use of <constant>V4L2_TUNER_MODE_STEREO</constant> for this purpose |
| 1976 | is deprecated now. See the &VIDIOC-G-TUNER; section for |
| 1977 | details.</para> |
| 1978 | </listitem> |
| 1979 | </orderedlist> |
| 1980 | </section> |
| 1981 | |
| 1982 | <section> |
| 1983 | <title>V4L2 spec erratum 2006-09-23 (Draft 0.15)</title> |
| 1984 | <orderedlist> |
| 1985 | <listitem> |
| 1986 | <para>In various places |
| 1987 | <constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> and |
| 1988 | <constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant> of the sliced VBI |
| 1989 | interface were not mentioned along with other buffer types.</para> |
| 1990 | </listitem> |
| 1991 | |
| 1992 | <listitem> |
| 1993 | <para>In <xref linkend="vidioc-g-audio" /> it was clarified |
| 1994 | that the &v4l2-audio; <structfield>mode</structfield> field is a flags |
| 1995 | field.</para> |
| 1996 | </listitem> |
| 1997 | |
| 1998 | <listitem> |
| 1999 | <para><xref linkend="vidioc-querycap" /> did not mention the |
| 2000 | sliced VBI and radio capability flags.</para> |
| 2001 | </listitem> |
| 2002 | |
| 2003 | <listitem> |
| 2004 | <para>In <xref linkend="vidioc-g-frequency" /> it was |
| 2005 | clarified that applications must initialize the tuner |
| 2006 | <structfield>type</structfield> field of &v4l2-frequency; before |
| 2007 | calling &VIDIOC-S-FREQUENCY;.</para> |
| 2008 | </listitem> |
| 2009 | |
| 2010 | <listitem> |
| 2011 | <para>The <structfield>reserved</structfield> array |
| 2012 | in &v4l2-requestbuffers; has 2 elements, not 32.</para> |
| 2013 | </listitem> |
| 2014 | |
| 2015 | <listitem> |
| 2016 | <para>In <xref linkend="output" /> and <xref |
| 2017 | linkend="raw-vbi" /> the device file names |
| 2018 | <filename>/dev/vout</filename> which never caught on were replaced |
| 2019 | by <filename>/dev/video</filename>.</para> |
| 2020 | </listitem> |
| 2021 | |
| 2022 | <listitem> |
| 2023 | <para>With Linux 2.6.15 the possible range for VBI device minor |
| 2024 | numbers was extended from 224-239 to 224-255. Accordingly device file names |
| 2025 | <filename>/dev/vbi0</filename> to <filename>/dev/vbi31</filename> are |
| 2026 | possible now.</para> |
| 2027 | </listitem> |
| 2028 | </orderedlist> |
| 2029 | </section> |
| 2030 | |
| 2031 | <section> |
| 2032 | <title>V4L2 in Linux 2.6.18</title> |
| 2033 | <orderedlist> |
| 2034 | <listitem> |
| 2035 | <para>New ioctls &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; |
| 2036 | and &VIDIOC-TRY-EXT-CTRLS; were added, a flag to skip unsupported |
| 2037 | controls with &VIDIOC-QUERYCTRL;, new control types |
| 2038 | <constant>V4L2_CTRL_TYPE_INTEGER64</constant> and |
| 2039 | <constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant> (<xref |
| 2040 | linkend="v4l2-ctrl-type" />), and new control flags |
| 2041 | <constant>V4L2_CTRL_FLAG_READ_ONLY</constant>, |
| 2042 | <constant>V4L2_CTRL_FLAG_UPDATE</constant>, |
| 2043 | <constant>V4L2_CTRL_FLAG_INACTIVE</constant> and |
| 2044 | <constant>V4L2_CTRL_FLAG_SLIDER</constant> (<xref |
| 2045 | linkend="control-flags" />). See <xref |
| 2046 | linkend="extended-controls" /> for details.</para> |
| 2047 | </listitem> |
| 2048 | </orderedlist> |
| 2049 | </section> |
| 2050 | |
| 2051 | <section> |
| 2052 | <title>V4L2 in Linux 2.6.19</title> |
| 2053 | <orderedlist> |
| 2054 | <listitem> |
| 2055 | <para>In &v4l2-sliced-vbi-cap; a buffer type field was added |
| 2056 | replacing a reserved field. Note on architectures where the size of |
| 2057 | enum types differs from int types the size of the structure changed. |
| 2058 | The &VIDIOC-G-SLICED-VBI-CAP; ioctl was redefined from being read-only |
| 2059 | to write-read. Applications must initialize the type field and clear |
| 2060 | the reserved fields now. These changes may <emphasis>break the |
| 2061 | compatibility</emphasis> with older drivers and applications.</para> |
| 2062 | </listitem> |
| 2063 | |
| 2064 | <listitem> |
| 2065 | <para>The ioctls &VIDIOC-ENUM-FRAMESIZES; and |
| 2066 | &VIDIOC-ENUM-FRAMEINTERVALS; were added.</para> |
| 2067 | </listitem> |
| 2068 | |
| 2069 | <listitem> |
| 2070 | <para>A new pixel format <constant>V4L2_PIX_FMT_RGB444</constant> (<xref |
| 2071 | linkend="rgb-formats" />) was added.</para> |
| 2072 | </listitem> |
| 2073 | </orderedlist> |
| 2074 | </section> |
| 2075 | |
| 2076 | <section> |
| 2077 | <title>V4L2 spec erratum 2006-10-12 (Draft 0.17)</title> |
| 2078 | <orderedlist> |
| 2079 | <listitem> |
| 2080 | <para><constant>V4L2_PIX_FMT_HM12</constant> (<xref |
| 2081 | linkend="reserved-formats" />) is a YUV 4:2:0, not 4:2:2 format.</para> |
| 2082 | </listitem> |
| 2083 | </orderedlist> |
| 2084 | </section> |
| 2085 | |
| 2086 | <section> |
| 2087 | <title>V4L2 in Linux 2.6.21</title> |
| 2088 | <orderedlist> |
| 2089 | <listitem> |
| 2090 | <para>The <filename>videodev2.h</filename> header file is |
| 2091 | now dual licensed under GNU General Public License version two or |
| 2092 | later, and under a 3-clause BSD-style license.</para> |
| 2093 | </listitem> |
| 2094 | </orderedlist> |
| 2095 | </section> |
| 2096 | |
| 2097 | <section> |
| 2098 | <title>V4L2 in Linux 2.6.22</title> |
| 2099 | <orderedlist> |
| 2100 | <listitem> |
| 2101 | <para>Two new field orders |
| 2102 | <constant>V4L2_FIELD_INTERLACED_TB</constant> and |
| 2103 | <constant>V4L2_FIELD_INTERLACED_BT</constant> were |
| 2104 | added. See <xref linkend="v4l2-field" /> for details.</para> |
| 2105 | </listitem> |
| 2106 | |
| 2107 | <listitem> |
| 2108 | <para>Three new clipping/blending methods with a global or |
| 2109 | straight or inverted local alpha value were added to the video overlay |
| 2110 | interface. See the description of the &VIDIOC-G-FBUF; and |
| 2111 | &VIDIOC-S-FBUF; ioctls for details.</para> |
| 2112 | <para>A new <structfield>global_alpha</structfield> field |
| 2113 | was added to <link |
| 2114 | linkend="v4l2-window"><structname>v4l2_window</structname></link>, |
| 2115 | extending the structure. This may <emphasis>break |
| 2116 | compatibility</emphasis> with applications using a struct |
| 2117 | <structname>v4l2_window</structname> directly. However the <link |
| 2118 | linkend="vidioc-g-fmt">VIDIOC_G/S/TRY_FMT</link> ioctls, which take a |
| 2119 | pointer to a <link linkend="v4l2-format">v4l2_format</link> parent |
| 2120 | structure with padding bytes at the end, are not affected.</para> |
| 2121 | </listitem> |
| 2122 | |
| 2123 | <listitem> |
| 2124 | <para>The format of the <structfield>chromakey</structfield> |
| 2125 | field in &v4l2-window; changed from "host order RGB32" to a pixel |
| 2126 | value in the same format as the framebuffer. This may <emphasis>break |
| 2127 | compatibility</emphasis> with existing applications. Drivers |
| 2128 | supporting the "host order RGB32" format are not known.</para> |
| 2129 | </listitem> |
| 2130 | |
| 2131 | </orderedlist> |
| 2132 | </section> |
| 2133 | |
| 2134 | <section> |
| 2135 | <title>V4L2 in Linux 2.6.24</title> |
| 2136 | <orderedlist> |
| 2137 | <listitem> |
| 2138 | <para>The pixel formats |
| 2139 | <constant>V4L2_PIX_FMT_PAL8</constant>, |
| 2140 | <constant>V4L2_PIX_FMT_YUV444</constant>, |
| 2141 | <constant>V4L2_PIX_FMT_YUV555</constant>, |
| 2142 | <constant>V4L2_PIX_FMT_YUV565</constant> and |
| 2143 | <constant>V4L2_PIX_FMT_YUV32</constant> were added.</para> |
| 2144 | </listitem> |
| 2145 | </orderedlist> |
| 2146 | </section> |
| 2147 | |
| 2148 | <section> |
| 2149 | <title>V4L2 in Linux 2.6.25</title> |
| 2150 | <orderedlist> |
| 2151 | <listitem> |
| 2152 | <para>The pixel formats <link linkend="V4L2-PIX-FMT-Y16"> |
| 2153 | <constant>V4L2_PIX_FMT_Y16</constant></link> and <link |
| 2154 | linkend="V4L2-PIX-FMT-SBGGR16"> |
| 2155 | <constant>V4L2_PIX_FMT_SBGGR16</constant></link> were added.</para> |
| 2156 | </listitem> |
| 2157 | <listitem> |
| 2158 | <para>New <link linkend="control">controls</link> |
| 2159 | <constant>V4L2_CID_POWER_LINE_FREQUENCY</constant>, |
| 2160 | <constant>V4L2_CID_HUE_AUTO</constant>, |
| 2161 | <constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant>, |
| 2162 | <constant>V4L2_CID_SHARPNESS</constant> and |
| 2163 | <constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant> were added. The |
| 2164 | controls <constant>V4L2_CID_BLACK_LEVEL</constant>, |
| 2165 | <constant>V4L2_CID_WHITENESS</constant>, |
| 2166 | <constant>V4L2_CID_HCENTER</constant> and |
| 2167 | <constant>V4L2_CID_VCENTER</constant> were deprecated. |
| 2168 | </para> |
| 2169 | </listitem> |
| 2170 | <listitem> |
| 2171 | <para>A <link linkend="camera-controls">Camera controls |
| 2172 | class</link> was added, with the new controls |
| 2173 | <constant>V4L2_CID_EXPOSURE_AUTO</constant>, |
| 2174 | <constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant>, |
| 2175 | <constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant>, |
| 2176 | <constant>V4L2_CID_PAN_RELATIVE</constant>, |
| 2177 | <constant>V4L2_CID_TILT_RELATIVE</constant>, |
| 2178 | <constant>V4L2_CID_PAN_RESET</constant>, |
| 2179 | <constant>V4L2_CID_TILT_RESET</constant>, |
| 2180 | <constant>V4L2_CID_PAN_ABSOLUTE</constant>, |
| 2181 | <constant>V4L2_CID_TILT_ABSOLUTE</constant>, |
| 2182 | <constant>V4L2_CID_FOCUS_ABSOLUTE</constant>, |
| 2183 | <constant>V4L2_CID_FOCUS_RELATIVE</constant> and |
| 2184 | <constant>V4L2_CID_FOCUS_AUTO</constant>.</para> |
| 2185 | </listitem> |
| 2186 | <listitem> |
| 2187 | <para>The <constant>VIDIOC_G_MPEGCOMP</constant> and |
| 2188 | <constant>VIDIOC_S_MPEGCOMP</constant> ioctls, which were superseded |
| 2189 | by the <link linkend="extended-controls">extended controls</link> |
| 2190 | interface in Linux 2.6.18, where finally removed from the |
| 2191 | <filename>videodev2.h</filename> header file.</para> |
| 2192 | </listitem> |
| 2193 | </orderedlist> |
| 2194 | </section> |
| 2195 | |
| 2196 | <section> |
| 2197 | <title>V4L2 in Linux 2.6.26</title> |
| 2198 | <orderedlist> |
| 2199 | <listitem> |
| 2200 | <para>The pixel formats |
| 2201 | <constant>V4L2_PIX_FMT_Y16</constant> and |
| 2202 | <constant>V4L2_PIX_FMT_SBGGR16</constant> were added.</para> |
| 2203 | </listitem> |
| 2204 | <listitem> |
| 2205 | <para>Added user controls |
| 2206 | <constant>V4L2_CID_CHROMA_AGC</constant> and |
| 2207 | <constant>V4L2_CID_COLOR_KILLER</constant>.</para> |
| 2208 | </listitem> |
| 2209 | </orderedlist> |
| 2210 | </section> |
| 2211 | |
| 2212 | <section> |
| 2213 | <title>V4L2 in Linux 2.6.27</title> |
| 2214 | <orderedlist> |
| 2215 | <listitem> |
| 2216 | <para>The &VIDIOC-S-HW-FREQ-SEEK; ioctl and the |
| 2217 | <constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability were added.</para> |
| 2218 | </listitem> |
| 2219 | <listitem> |
| 2220 | <para>The pixel formats |
| 2221 | <constant>V4L2_PIX_FMT_YVYU</constant>, |
| 2222 | <constant>V4L2_PIX_FMT_PCA501</constant>, |
| 2223 | <constant>V4L2_PIX_FMT_PCA505</constant>, |
| 2224 | <constant>V4L2_PIX_FMT_PCA508</constant>, |
| 2225 | <constant>V4L2_PIX_FMT_PCA561</constant>, |
| 2226 | <constant>V4L2_PIX_FMT_SGBRG8</constant>, |
| 2227 | <constant>V4L2_PIX_FMT_PAC207</constant> and |
| 2228 | <constant>V4L2_PIX_FMT_PJPG</constant> were added.</para> |
| 2229 | </listitem> |
| 2230 | </orderedlist> |
| 2231 | </section> |
| 2232 | |
| 2233 | <section> |
| 2234 | <title>V4L2 in Linux 2.6.28</title> |
| 2235 | <orderedlist> |
| 2236 | <listitem> |
| 2237 | <para>Added <constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant> and |
| 2238 | <constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant> MPEG audio encodings.</para> |
| 2239 | </listitem> |
| 2240 | <listitem> |
| 2241 | <para>Added <constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant> MPEG |
| 2242 | video encoding.</para> |
| 2243 | </listitem> |
| 2244 | <listitem> |
| 2245 | <para>The pixel formats |
| 2246 | <constant>V4L2_PIX_FMT_SGRBG10</constant> and |
| 2247 | <constant>V4L2_PIX_FMT_SGRBG10DPCM8</constant> were added.</para> |
| 2248 | </listitem> |
| 2249 | </orderedlist> |
| 2250 | </section> |
| 2251 | |
| 2252 | <section> |
| 2253 | <title>V4L2 in Linux 2.6.29</title> |
| 2254 | <orderedlist> |
| 2255 | <listitem> |
| 2256 | <para>The <constant>VIDIOC_G_CHIP_IDENT</constant> ioctl was renamed |
Hans Verkuil | a6edca3 | 2013-05-26 09:45:23 -0300 | [diff] [blame] | 2257 | to <constant>VIDIOC_G_CHIP_IDENT_OLD</constant> and <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2258 | was introduced in its place. The old struct <structname>v4l2_chip_ident</structname> |
| 2259 | was renamed to <structname id="v4l2-chip-ident-old">v4l2_chip_ident_old</structname>.</para> |
| 2260 | </listitem> |
| 2261 | <listitem> |
| 2262 | <para>The pixel formats |
| 2263 | <constant>V4L2_PIX_FMT_VYUY</constant>, |
| 2264 | <constant>V4L2_PIX_FMT_NV16</constant> and |
| 2265 | <constant>V4L2_PIX_FMT_NV61</constant> were added.</para> |
| 2266 | </listitem> |
| 2267 | <listitem> |
| 2268 | <para>Added camera controls |
| 2269 | <constant>V4L2_CID_ZOOM_ABSOLUTE</constant>, |
| 2270 | <constant>V4L2_CID_ZOOM_RELATIVE</constant>, |
| 2271 | <constant>V4L2_CID_ZOOM_CONTINUOUS</constant> and |
| 2272 | <constant>V4L2_CID_PRIVACY</constant>.</para> |
| 2273 | </listitem> |
| 2274 | </orderedlist> |
| 2275 | </section> |
| 2276 | <section> |
| 2277 | <title>V4L2 in Linux 2.6.30</title> |
| 2278 | <orderedlist> |
| 2279 | <listitem> |
| 2280 | <para>New control flag <constant>V4L2_CTRL_FLAG_WRITE_ONLY</constant> was added.</para> |
| 2281 | </listitem> |
| 2282 | <listitem> |
| 2283 | <para>New control <constant>V4L2_CID_COLORFX</constant> was added.</para> |
| 2284 | </listitem> |
Hans Verkuil | b33f5f8 | 2009-12-03 01:32:12 -0300 | [diff] [blame] | 2285 | </orderedlist> |
| 2286 | </section> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2287 | <section> |
| 2288 | <title>V4L2 in Linux 2.6.32</title> |
| 2289 | <orderedlist> |
| 2290 | <listitem> |
| 2291 | <para>In order to be easier to compare a V4L2 API and a kernel |
| 2292 | version, now V4L2 API is numbered using the Linux Kernel version numeration.</para> |
| 2293 | </listitem> |
| 2294 | <listitem> |
| 2295 | <para>Finalized the RDS capture API. See <xref linkend="rds" /> for |
| 2296 | more information.</para> |
| 2297 | </listitem> |
| 2298 | <listitem> |
| 2299 | <para>Added new capabilities for modulators and RDS encoders.</para> |
| 2300 | </listitem> |
| 2301 | <listitem> |
| 2302 | <para>Add description for libv4l API.</para> |
| 2303 | </listitem> |
| 2304 | <listitem> |
| 2305 | <para>Added support for string controls via new type <constant>V4L2_CTRL_TYPE_STRING</constant>.</para> |
| 2306 | </listitem> |
| 2307 | <listitem> |
| 2308 | <para>Added <constant>V4L2_CID_BAND_STOP_FILTER</constant> documentation.</para> |
| 2309 | </listitem> |
| 2310 | <listitem> |
| 2311 | <para>Added FM Modulator (FM TX) Extended Control Class: <constant>V4L2_CTRL_CLASS_FM_TX</constant> and their Control IDs.</para> |
| 2312 | </listitem> |
Andrey Smirnov | b4e96a7 | 2013-03-26 22:47:24 -0300 | [diff] [blame] | 2313 | <listitem> |
| 2314 | <para>Added FM Receiver (FM RX) Extended Control Class: <constant>V4L2_CTRL_CLASS_FM_RX</constant> and their Control IDs.</para> |
| 2315 | </listitem> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2316 | <listitem> |
| 2317 | <para>Added Remote Controller chapter, describing the default Remote Controller mapping for media devices.</para> |
| 2318 | </listitem> |
Hans Verkuil | b33f5f8 | 2009-12-03 01:32:12 -0300 | [diff] [blame] | 2319 | </orderedlist> |
| 2320 | </section> |
| 2321 | <section> |
| 2322 | <title>V4L2 in Linux 2.6.33</title> |
| 2323 | <orderedlist> |
| 2324 | <listitem> |
| 2325 | <para>Added support for Digital Video timings in order to support HDTV receivers and transmitters.</para> |
| 2326 | </listitem> |
| 2327 | </orderedlist> |
| 2328 | </section> |
Laurent Pinchart | 48213fe | 2010-01-20 12:12:57 -0300 | [diff] [blame] | 2329 | <section> |
| 2330 | <title>V4L2 in Linux 2.6.34</title> |
| 2331 | <orderedlist> |
| 2332 | <listitem> |
| 2333 | <para>Added |
| 2334 | <constant>V4L2_CID_IRIS_ABSOLUTE</constant> and |
| 2335 | <constant>V4L2_CID_IRIS_RELATIVE</constant> controls to the |
| 2336 | <link linkend="camera-controls">Camera controls class</link>. |
| 2337 | </para> |
| 2338 | </listitem> |
| 2339 | </orderedlist> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2340 | </section> |
Hans Verkuil | f44026d | 2010-08-06 12:52:43 -0300 | [diff] [blame] | 2341 | <section> |
| 2342 | <title>V4L2 in Linux 2.6.37</title> |
| 2343 | <orderedlist> |
| 2344 | <listitem> |
| 2345 | <para>Remove the vtx (videotext/teletext) API. This API was no longer |
| 2346 | used and no hardware exists to verify the API. Nor were any userspace applications found |
| 2347 | that used it. It was originally scheduled for removal in 2.6.35. |
| 2348 | </para> |
| 2349 | </listitem> |
| 2350 | </orderedlist> |
| 2351 | </section> |
Pawel Osciak | 53b5d57 | 2011-01-07 01:41:33 -0300 | [diff] [blame] | 2352 | <section> |
Pawel Osciak | f0e3b64 | 2011-03-13 15:20:22 -0300 | [diff] [blame] | 2353 | <title>V4L2 in Linux 2.6.39</title> |
Pawel Osciak | 53b5d57 | 2011-01-07 01:41:33 -0300 | [diff] [blame] | 2354 | <orderedlist> |
| 2355 | <listitem> |
Pawel Osciak | f0e3b64 | 2011-03-13 15:20:22 -0300 | [diff] [blame] | 2356 | <para>The old VIDIOC_*_OLD symbols and V4L1 support were removed.</para> |
| 2357 | </listitem> |
| 2358 | <listitem> |
Pawel Osciak | 53b5d57 | 2011-01-07 01:41:33 -0300 | [diff] [blame] | 2359 | <para>Multi-planar API added. Does not affect the compatibility of |
| 2360 | current drivers and applications. See |
| 2361 | <link linkend="planar-apis">multi-planar API</link> |
| 2362 | for details.</para> |
| 2363 | </listitem> |
| 2364 | </orderedlist> |
| 2365 | </section> |
Hans Verkuil | aec67f0 | 2011-05-23 07:36:55 -0300 | [diff] [blame] | 2366 | <section> |
| 2367 | <title>V4L2 in Linux 3.1</title> |
| 2368 | <orderedlist> |
| 2369 | <listitem> |
| 2370 | <para>VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one.</para> |
| 2371 | <para>Standardize an error code for invalid ioctl.</para> |
| 2372 | <para>Added V4L2_CTRL_TYPE_BITMASK.</para> |
| 2373 | </listitem> |
| 2374 | </orderedlist> |
| 2375 | </section> |
Hans Verkuil | 74a4579 | 2011-08-26 07:31:13 -0300 | [diff] [blame] | 2376 | <section> |
| 2377 | <title>V4L2 in Linux 3.2</title> |
| 2378 | <orderedlist> |
| 2379 | <listitem> |
| 2380 | <para>V4L2_CTRL_FLAG_VOLATILE was added to signal volatile controls to userspace.</para> |
| 2381 | </listitem> |
Tomasz Stanislawski | 8af4922 | 2011-08-19 07:00:04 -0300 | [diff] [blame] | 2382 | <listitem> |
Sakari Ailus | 64b9ce8 | 2012-06-01 13:56:53 -0300 | [diff] [blame] | 2383 | <para>Add selection API for extended control over cropping |
| 2384 | and composing. Does not affect the compatibility of current |
| 2385 | drivers and applications. See <link |
| 2386 | linkend="selection-api"> selection API </link> for |
| 2387 | details.</para> |
Tomasz Stanislawski | 8af4922 | 2011-08-19 07:00:04 -0300 | [diff] [blame] | 2388 | </listitem> |
Hans Verkuil | 74a4579 | 2011-08-26 07:31:13 -0300 | [diff] [blame] | 2389 | </orderedlist> |
| 2390 | </section> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2391 | |
Sylwester Nawrocki | cc1d327 | 2011-11-14 08:48:18 -0300 | [diff] [blame] | 2392 | <section> |
| 2393 | <title>V4L2 in Linux 3.3</title> |
| 2394 | <orderedlist> |
| 2395 | <listitem> |
| 2396 | <para>Added <constant>V4L2_CID_ALPHA_COMPONENT</constant> control |
| 2397 | to the <link linkend="control">User controls class</link>. |
| 2398 | </para> |
| 2399 | </listitem> |
Hans Verkuil | 583aa3a | 2012-01-11 06:45:05 -0300 | [diff] [blame] | 2400 | <listitem> |
| 2401 | <para>Added the device_caps field to struct v4l2_capabilities and added the new |
| 2402 | V4L2_CAP_DEVICE_CAPS capability.</para> |
| 2403 | </listitem> |
Sylwester Nawrocki | cc1d327 | 2011-11-14 08:48:18 -0300 | [diff] [blame] | 2404 | </orderedlist> |
| 2405 | </section> |
| 2406 | |
Sylwester Nawrocki | 29fa0ee | 2012-01-20 15:38:50 -0300 | [diff] [blame] | 2407 | <section> |
| 2408 | <title>V4L2 in Linux 3.4</title> |
| 2409 | <orderedlist> |
| 2410 | <listitem> |
| 2411 | <para>Added <link linkend="jpeg-controls">JPEG compression control |
| 2412 | class</link>.</para> |
| 2413 | </listitem> |
Hans Verkuil | 7dcc606 | 2012-05-15 08:04:28 -0300 | [diff] [blame] | 2414 | <listitem> |
| 2415 | <para>Extended the DV Timings API: |
| 2416 | &VIDIOC-ENUM-DV-TIMINGS;, &VIDIOC-QUERY-DV-TIMINGS; and |
| 2417 | &VIDIOC-DV-TIMINGS-CAP;.</para> |
| 2418 | </listitem> |
Sylwester Nawrocki | 29fa0ee | 2012-01-20 15:38:50 -0300 | [diff] [blame] | 2419 | </orderedlist> |
| 2420 | </section> |
| 2421 | |
Sakari Ailus | 6ec299f | 2011-08-06 16:13:47 -0300 | [diff] [blame] | 2422 | <section> |
| 2423 | <title>V4L2 in Linux 3.5</title> |
| 2424 | <orderedlist> |
| 2425 | <listitem> |
| 2426 | <para>Added integer menus, the new type will be |
| 2427 | V4L2_CTRL_TYPE_INTEGER_MENU.</para> |
| 2428 | </listitem> |
Sakari Ailus | 955f645 | 2011-12-12 18:17:25 -0300 | [diff] [blame] | 2429 | <listitem> |
| 2430 | <para>Added selection API for V4L2 subdev interface: |
| 2431 | &VIDIOC-SUBDEV-G-SELECTION; and |
| 2432 | &VIDIOC-SUBDEV-S-SELECTION;.</para> |
| 2433 | </listitem> |
Sylwester Nawrocki | 6491d1a | 2012-04-02 06:40:19 -0300 | [diff] [blame] | 2434 | <listitem> |
| 2435 | <para> Added <constant>V4L2_COLORFX_ANTIQUE</constant>, |
| 2436 | <constant>V4L2_COLORFX_ART_FREEZE</constant>, |
| 2437 | <constant>V4L2_COLORFX_AQUA</constant>, |
| 2438 | <constant>V4L2_COLORFX_SILHOUETTE</constant>, |
| 2439 | <constant>V4L2_COLORFX_SOLARIZATION</constant>, |
| 2440 | <constant>V4L2_COLORFX_VIVID</constant> and |
| 2441 | <constant>V4L2_COLORFX_ARBITRARY_CBCR</constant> menu items |
| 2442 | to the <constant>V4L2_CID_COLORFX</constant> control.</para> |
| 2443 | </listitem> |
| 2444 | <listitem> |
| 2445 | <para> Added <constant>V4L2_CID_COLORFX_CBCR</constant> control.</para> |
| 2446 | </listitem> |
Sylwester Nawrocki | 2272ab6 | 2012-05-11 06:37:03 -0300 | [diff] [blame] | 2447 | <listitem> |
| 2448 | <para> Added camera controls <constant>V4L2_CID_AUTO_EXPOSURE_BIAS</constant>, |
| 2449 | <constant>V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE</constant>, |
| 2450 | <constant>V4L2_CID_IMAGE_STABILIZATION</constant>, |
| 2451 | <constant>V4L2_CID_ISO_SENSITIVITY</constant>, |
| 2452 | <constant>V4L2_CID_ISO_SENSITIVITY_AUTO</constant>, |
| 2453 | <constant>V4L2_CID_EXPOSURE_METERING</constant>, |
| 2454 | <constant>V4L2_CID_SCENE_MODE</constant>, |
| 2455 | <constant>V4L2_CID_3A_LOCK</constant>, |
| 2456 | <constant>V4L2_CID_AUTO_FOCUS_START</constant>, |
| 2457 | <constant>V4L2_CID_AUTO_FOCUS_STOP</constant>, |
| 2458 | <constant>V4L2_CID_AUTO_FOCUS_STATUS</constant> and |
| 2459 | <constant>V4L2_CID_AUTO_FOCUS_RANGE</constant>. |
| 2460 | </para> |
| 2461 | </listitem> |
Sakari Ailus | 6ec299f | 2011-08-06 16:13:47 -0300 | [diff] [blame] | 2462 | </orderedlist> |
| 2463 | </section> |
| 2464 | |
Sakari Ailus | 2b719d7 | 2012-05-02 09:40:03 -0300 | [diff] [blame] | 2465 | <section> |
Nicolas THERY | b67a39e | 2012-07-12 12:12:12 -0300 | [diff] [blame] | 2466 | <title>V4L2 in Linux 3.6</title> |
Sakari Ailus | 2b719d7 | 2012-05-02 09:40:03 -0300 | [diff] [blame] | 2467 | <orderedlist> |
| 2468 | <listitem> |
| 2469 | <para>Replaced <structfield>input</structfield> in |
| 2470 | <structname>v4l2_buffer</structname> by |
| 2471 | <structfield>reserved2</structfield> and removed |
| 2472 | <constant>V4L2_BUF_FLAG_INPUT</constant>.</para> |
| 2473 | </listitem> |
Sylwester Nawrocki | f0476a8 | 2012-07-26 09:30:00 -0300 | [diff] [blame] | 2474 | <listitem> |
| 2475 | <para>Added V4L2_CAP_VIDEO_M2M and V4L2_CAP_VIDEO_M2M_MPLANE capabilities.</para> |
| 2476 | </listitem> |
Hans Verkuil | 5012131 | 2012-07-05 06:54:38 -0300 | [diff] [blame] | 2477 | <listitem> |
| 2478 | <para>Added support for frequency band enumerations: &VIDIOC-ENUM-FREQ-BANDS;.</para> |
| 2479 | </listitem> |
| 2480 | </orderedlist> |
| 2481 | </section> |
| 2482 | |
Sakari Ailus | 1202ecd | 2012-10-21 16:02:47 -0300 | [diff] [blame] | 2483 | <section> |
| 2484 | <title>V4L2 in Linux 3.9</title> |
| 2485 | <orderedlist> |
| 2486 | <listitem> |
| 2487 | <para>Added timestamp types to |
| 2488 | <structfield>flags</structfield> field in |
| 2489 | <structname>v4l2_buffer</structname>. See <xref |
| 2490 | linkend="buffer-flags" />.</para> |
| 2491 | </listitem> |
Sylwester Nawrocki | 2ccbe77 | 2013-01-19 15:51:55 -0300 | [diff] [blame] | 2492 | <listitem> |
| 2493 | <para>Added <constant>V4L2_EVENT_CTRL_CH_RANGE</constant> control event |
| 2494 | changes flag. See <xref linkend="changes-flags"/>.</para> |
| 2495 | </listitem> |
Sakari Ailus | 1202ecd | 2012-10-21 16:02:47 -0300 | [diff] [blame] | 2496 | </orderedlist> |
| 2497 | </section> |
| 2498 | |
Hans Verkuil | 4e5f113 | 2013-03-24 06:08:00 -0300 | [diff] [blame] | 2499 | <section> |
| 2500 | <title>V4L2 in Linux 3.10</title> |
| 2501 | <orderedlist> |
| 2502 | <listitem> |
| 2503 | <para>Removed obsolete and unused DV_PRESET ioctls |
| 2504 | VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET, VIDIOC_QUERY_DV_PRESET and |
| 2505 | VIDIOC_ENUM_DV_PRESET. Remove the related v4l2_input/output capability |
| 2506 | flags V4L2_IN_CAP_PRESETS and V4L2_OUT_CAP_PRESETS. |
| 2507 | </para> |
| 2508 | </listitem> |
Hans Verkuil | e3f7586 | 2013-03-25 08:49:15 -0300 | [diff] [blame] | 2509 | <listitem> |
Hans Verkuil | 96b03d2 | 2013-04-06 06:16:58 -0300 | [diff] [blame] | 2510 | <para>Added new debugging ioctl &VIDIOC-DBG-G-CHIP-INFO;. |
Hans Verkuil | e3f7586 | 2013-03-25 08:49:15 -0300 | [diff] [blame] | 2511 | </para> |
| 2512 | </listitem> |
Hans Verkuil | 4e5f113 | 2013-03-24 06:08:00 -0300 | [diff] [blame] | 2513 | </orderedlist> |
| 2514 | </section> |
| 2515 | |
Hans Verkuil | a6edca3 | 2013-05-26 09:45:23 -0300 | [diff] [blame] | 2516 | <section> |
| 2517 | <title>V4L2 in Linux 3.11</title> |
| 2518 | <orderedlist> |
| 2519 | <listitem> |
| 2520 | <para>Remove obsolete <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> ioctl. |
| 2521 | </para> |
| 2522 | </listitem> |
| 2523 | </orderedlist> |
| 2524 | </section> |
| 2525 | |
Ricardo Ribalda | f90580c | 2013-11-26 05:31:42 -0300 | [diff] [blame] | 2526 | <section> |
| 2527 | <title>V4L2 in Linux 3.14</title> |
| 2528 | <orderedlist> |
| 2529 | <listitem> |
| 2530 | <para> In struct <structname>v4l2_rect</structname>, the type |
| 2531 | of <structfield>width</structfield> and <structfield>height</structfield> |
| 2532 | fields changed from _s32 to _u32. |
| 2533 | </para> |
| 2534 | </listitem> |
| 2535 | </orderedlist> |
| 2536 | </section> |
| 2537 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2538 | <section id="other"> |
| 2539 | <title>Relation of V4L2 to other Linux multimedia APIs</title> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2540 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2541 | <section id="xvideo"> |
| 2542 | <title>X Video Extension</title> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2543 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2544 | <para>The X Video Extension (abbreviated XVideo or just Xv) is |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2545 | an extension of the X Window system, implemented for example by the |
| 2546 | XFree86 project. Its scope is similar to V4L2, an API to video capture |
| 2547 | and output devices for X clients. Xv allows applications to display |
| 2548 | live video in a window, send window contents to a TV output, and |
| 2549 | capture or output still images in XPixmaps<footnote> |
| 2550 | <para>This is not implemented in XFree86.</para> |
| 2551 | </footnote>. With their implementation XFree86 makes the |
| 2552 | extension available across many operating systems and |
| 2553 | architectures.</para> |
| 2554 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2555 | <para>Because the driver is embedded into the X server Xv has a |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2556 | number of advantages over the V4L2 <link linkend="overlay">video |
| 2557 | overlay interface</link>. The driver can easily determine the overlay |
| 2558 | target, &ie; visible graphics memory or off-screen buffers for a |
| 2559 | destructive overlay. It can program the RAMDAC for a non-destructive |
| 2560 | overlay, scaling or color-keying, or the clipping functions of the |
| 2561 | video capture hardware, always in sync with drawing operations or |
| 2562 | windows moving or changing their stacking order.</para> |
| 2563 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2564 | <para>To combine the advantages of Xv and V4L a special Xv |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2565 | driver exists in XFree86 and XOrg, just programming any overlay capable |
| 2566 | Video4Linux device it finds. To enable it |
| 2567 | <filename>/etc/X11/XF86Config</filename> must contain these lines:</para> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2568 | <para><screen> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2569 | Section "Module" |
| 2570 | Load "v4l" |
| 2571 | EndSection</screen></para> |
| 2572 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2573 | <para>As of XFree86 4.2 this driver still supports only V4L |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2574 | ioctls, however it should work just fine with all V4L2 devices through |
| 2575 | the V4L2 backward-compatibility layer. Since V4L2 permits multiple |
| 2576 | opens it is possible (if supported by the V4L2 driver) to capture |
| 2577 | video while an X client requested video overlay. Restrictions of |
| 2578 | simultaneous capturing and overlay are discussed in <xref |
| 2579 | linkend="overlay" /> apply.</para> |
| 2580 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2581 | <para>Only marginally related to V4L2, XFree86 extended Xv to |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2582 | support hardware YUV to RGB conversion and scaling for faster video |
| 2583 | playback, and added an interface to MPEG-2 decoding hardware. This API |
| 2584 | is useful to display images captured with V4L2 devices.</para> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2585 | </section> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2586 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2587 | <section> |
| 2588 | <title>Digital Video</title> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2589 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2590 | <para>V4L2 does not support digital terrestrial, cable or |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2591 | satellite broadcast. A separate project aiming at digital receivers |
| 2592 | exists. You can find its homepage at <ulink |
| 2593 | url="http://linuxtv.org">http://linuxtv.org</ulink>. The Linux DVB API |
| 2594 | has no connection to the V4L2 API except that drivers for hybrid |
| 2595 | hardware may support both.</para> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2596 | </section> |
| 2597 | |
| 2598 | <section> |
| 2599 | <title>Audio Interfaces</title> |
| 2600 | |
| 2601 | <para>[to do - OSS/ALSA]</para> |
| 2602 | </section> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2603 | </section> |
| 2604 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2605 | <section id="experimental"> |
| 2606 | <title>Experimental API Elements</title> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2607 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2608 | <para>The following V4L2 API elements are currently experimental |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2609 | and may change in the future.</para> |
| 2610 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2611 | <itemizedlist> |
| 2612 | <listitem> |
| 2613 | <para>Video Output Overlay (OSD) Interface, <xref |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2614 | linkend="osd" />.</para> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2615 | </listitem> |
Hans Verkuil | 7dcc606 | 2012-05-15 08:04:28 -0300 | [diff] [blame] | 2616 | <listitem> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2617 | <para>&VIDIOC-DBG-G-REGISTER; and &VIDIOC-DBG-S-REGISTER; |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2618 | ioctls.</para> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2619 | </listitem> |
| 2620 | <listitem> |
Hans Verkuil | a6edca3 | 2013-05-26 09:45:23 -0300 | [diff] [blame] | 2621 | <para>&VIDIOC-DBG-G-CHIP-INFO; ioctl.</para> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2622 | </listitem> |
Sakari Ailus | 7ba85fa | 2011-05-04 10:45:58 -0300 | [diff] [blame] | 2623 | <listitem> |
Hans Verkuil | 7dcc606 | 2012-05-15 08:04:28 -0300 | [diff] [blame] | 2624 | <para>&VIDIOC-ENUM-DV-TIMINGS;, &VIDIOC-QUERY-DV-TIMINGS; and |
| 2625 | &VIDIOC-DV-TIMINGS-CAP; ioctls.</para> |
| 2626 | </listitem> |
| 2627 | <listitem> |
Sakari Ailus | 7ba85fa | 2011-05-04 10:45:58 -0300 | [diff] [blame] | 2628 | <para>Flash API. <xref linkend="flash-controls" /></para> |
| 2629 | </listitem> |
Guennadi Liakhovetski | 5509328 | 2011-09-28 08:10:58 -0300 | [diff] [blame] | 2630 | <listitem> |
| 2631 | <para>&VIDIOC-CREATE-BUFS; and &VIDIOC-PREPARE-BUF; ioctls.</para> |
| 2632 | </listitem> |
Tomasz Stanislawski | 8af4922 | 2011-08-19 07:00:04 -0300 | [diff] [blame] | 2633 | <listitem> |
| 2634 | <para>Selection API. <xref linkend="selection-api" /></para> |
| 2635 | </listitem> |
Sakari Ailus | 955f645 | 2011-12-12 18:17:25 -0300 | [diff] [blame] | 2636 | <listitem> |
| 2637 | <para>Sub-device selection API: &VIDIOC-SUBDEV-G-SELECTION; |
| 2638 | and &VIDIOC-SUBDEV-S-SELECTION; ioctls.</para> |
| 2639 | </listitem> |
Sylwester Nawrocki | 2272ab6 | 2012-05-11 06:37:03 -0300 | [diff] [blame] | 2640 | <listitem> |
Hans Verkuil | 5012131 | 2012-07-05 06:54:38 -0300 | [diff] [blame] | 2641 | <para>Support for frequency band enumeration: &VIDIOC-ENUM-FREQ-BANDS; ioctl.</para> |
| 2642 | </listitem> |
Sylwester Nawrocki | d264248 | 2012-02-16 14:23:54 -0300 | [diff] [blame] | 2643 | <listitem> |
| 2644 | <para>Vendor and device specific media bus pixel formats. |
| 2645 | <xref linkend="v4l2-mbus-vendor-spec-fmts" />.</para> |
| 2646 | </listitem> |
Tomasz Stanislawski | 4b9c1cb | 2012-06-14 10:37:36 -0300 | [diff] [blame] | 2647 | <listitem> |
| 2648 | <para>Importing DMABUF file descriptors as a new IO method described |
| 2649 | in <xref linkend="dmabuf" />.</para> |
| 2650 | </listitem> |
Tomasz Stanislawski | 19b6ef5 | 2012-06-14 11:32:22 -0300 | [diff] [blame] | 2651 | <listitem> |
| 2652 | <para>Exporting DMABUF files using &VIDIOC-EXPBUF; ioctl.</para> |
| 2653 | </listitem> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2654 | </itemizedlist> |
| 2655 | </section> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2656 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2657 | <section id="obsolete"> |
| 2658 | <title>Obsolete API Elements</title> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2659 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2660 | <para>The following V4L2 API elements were superseded by new |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2661 | interfaces and should not be implemented in new drivers.</para> |
| 2662 | |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2663 | <itemizedlist> |
| 2664 | <listitem> |
| 2665 | <para><constant>VIDIOC_G_MPEGCOMP</constant> and |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2666 | <constant>VIDIOC_S_MPEGCOMP</constant> ioctls. Use Extended Controls, |
| 2667 | <xref linkend="extended-controls" />.</para> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2668 | </listitem> |
Sakari Ailus | 8766e86 | 2012-01-07 06:23:36 -0300 | [diff] [blame] | 2669 | <listitem> |
Hans Verkuil | 098cbc3 | 2013-03-24 06:09:29 -0300 | [diff] [blame] | 2670 | <para>VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET, VIDIOC_ENUM_DV_PRESETS and |
| 2671 | VIDIOC_QUERY_DV_PRESET ioctls. Use the DV Timings API (<xref linkend="dv-timings" />).</para> |
Hans Verkuil | 75916fd | 2012-05-01 05:29:07 -0300 | [diff] [blame] | 2672 | </listitem> |
| 2673 | <listitem> |
Sakari Ailus | 8766e86 | 2012-01-07 06:23:36 -0300 | [diff] [blame] | 2674 | <para><constant>VIDIOC_SUBDEV_G_CROP</constant> and |
| 2675 | <constant>VIDIOC_SUBDEV_S_CROP</constant> ioctls. Use |
| 2676 | <constant>VIDIOC_SUBDEV_G_SELECTION</constant> and |
| 2677 | <constant>VIDIOC_SUBDEV_S_SELECTION</constant>, <xref |
| 2678 | linkend="vidioc-subdev-g-selection" />.</para> |
| 2679 | </listitem> |
Hans Verkuil | e426e86 | 2010-04-06 10:32:19 -0300 | [diff] [blame] | 2680 | </itemizedlist> |
| 2681 | </section> |
Mauro Carvalho Chehab | 8e080c2 | 2009-09-13 22:16:04 -0300 | [diff] [blame] | 2682 | </section> |