| <refentry id="vidioc-g-dv-timings"> |
| <refmeta> |
| <refentrytitle>ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</refentrytitle> |
| &manvol; |
| </refmeta> |
| |
| <refnamediv> |
| <refname>VIDIOC_G_DV_TIMINGS</refname> |
| <refname>VIDIOC_S_DV_TIMINGS</refname> |
| <refpurpose>Get or set DV timings for input or output</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <funcsynopsis> |
| <funcprototype> |
| <funcdef>int <function>ioctl</function></funcdef> |
| <paramdef>int <parameter>fd</parameter></paramdef> |
| <paramdef>int <parameter>request</parameter></paramdef> |
| <paramdef>struct v4l2_dv_timings *<parameter>argp</parameter></paramdef> |
| </funcprototype> |
| </funcsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Arguments</title> |
| |
| <variablelist> |
| <varlistentry> |
| <term><parameter>fd</parameter></term> |
| <listitem> |
| <para>&fd;</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><parameter>request</parameter></term> |
| <listitem> |
| <para>VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><parameter>argp</parameter></term> |
| <listitem> |
| <para></para> |
| </listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Description</title> |
| <para>To set DV timings for the input or output, applications use the |
| <constant>VIDIOC_S_DV_TIMINGS</constant> ioctl and to get the current timings, |
| applications use the <constant>VIDIOC_G_DV_TIMINGS</constant> ioctl. The detailed timing |
| information is filled in using the structure &v4l2-dv-timings;. These ioctls take |
| a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported |
| or the timing values are not correct, the driver returns &EINVAL;.</para> |
| <para>The <filename>linux/v4l2-dv-timings.h</filename> header can be used to get the |
| timings of the formats in the <xref linkend="cea861" /> and <xref linkend="vesadmt" /> |
| standards. If the current input or output does not support DV timings (e.g. if |
| &VIDIOC-ENUMINPUT; does not set the <constant>V4L2_IN_CAP_DV_TIMINGS</constant> flag), then |
| &ENODATA; is returned.</para> |
| </refsect1> |
| |
| <refsect1> |
| &return-value; |
| |
| <variablelist> |
| <varlistentry> |
| <term><errorcode>EINVAL</errorcode></term> |
| <listitem> |
| <para>This ioctl is not supported, or the |
| <constant>VIDIOC_S_DV_TIMINGS</constant> parameter was unsuitable.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><errorcode>ENODATA</errorcode></term> |
| <listitem> |
| <para>Digital video timings are not supported for this input or output.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><errorcode>EBUSY</errorcode></term> |
| <listitem> |
| <para>The device is busy and therefore can not change the timings.</para> |
| </listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <table pgwide="1" frame="none" id="v4l2-bt-timings"> |
| <title>struct <structname>v4l2_bt_timings</structname></title> |
| <tgroup cols="3"> |
| &cs-str; |
| <tbody valign="top"> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>width</structfield></entry> |
| <entry>Width of the active video in pixels.</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>height</structfield></entry> |
| <entry>Height of the active video frame in lines. So for interlaced formats the |
| height of the active video in each field is <structfield>height</structfield>/2.</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>interlaced</structfield></entry> |
| <entry>Progressive (0) or interlaced (1)</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>polarities</structfield></entry> |
| <entry>This is a bit mask that defines polarities of sync signals. |
| bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If the bit is set |
| (1) it is positive polarity and if is cleared (0), it is negative polarity.</entry> |
| </row> |
| <row> |
| <entry>__u64</entry> |
| <entry><structfield>pixelclock</structfield></entry> |
| <entry>Pixel clock in Hz. Ex. 74.25MHz->74250000</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>hfrontporch</structfield></entry> |
| <entry>Horizontal front porch in pixels</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>hsync</structfield></entry> |
| <entry>Horizontal sync length in pixels</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>hbackporch</structfield></entry> |
| <entry>Horizontal back porch in pixels</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>vfrontporch</structfield></entry> |
| <entry>Vertical front porch in lines. For interlaced formats this refers to the |
| odd field (aka field 1).</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>vsync</structfield></entry> |
| <entry>Vertical sync length in lines. For interlaced formats this refers to the |
| odd field (aka field 1).</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>vbackporch</structfield></entry> |
| <entry>Vertical back porch in lines. For interlaced formats this refers to the |
| odd field (aka field 1).</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>il_vfrontporch</structfield></entry> |
| <entry>Vertical front porch in lines for the even field (aka field 2) of |
| interlaced field formats.</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>il_vsync</structfield></entry> |
| <entry>Vertical sync length in lines for the even field (aka field 2) of |
| interlaced field formats.</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>il_vbackporch</structfield></entry> |
| <entry>Vertical back porch in lines for the even field (aka field 2) of |
| interlaced field formats.</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>standards</structfield></entry> |
| <entry>The video standard(s) this format belongs to. This will be filled in by |
| the driver. Applications must set this to 0. See <xref linkend="dv-bt-standards"/> |
| for a list of standards.</entry> |
| </row> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>flags</structfield></entry> |
| <entry>Several flags giving more information about the format. |
| See <xref linkend="dv-bt-flags"/> for a description of the flags. |
| </entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| |
| <table pgwide="1" frame="none" id="v4l2-dv-timings"> |
| <title>struct <structname>v4l2_dv_timings</structname></title> |
| <tgroup cols="4"> |
| &cs-str; |
| <tbody valign="top"> |
| <row> |
| <entry>__u32</entry> |
| <entry><structfield>type</structfield></entry> |
| <entry></entry> |
| <entry>Type of DV timings as listed in <xref linkend="dv-timing-types"/>.</entry> |
| </row> |
| <row> |
| <entry>union</entry> |
| <entry><structfield></structfield></entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry></entry> |
| <entry>&v4l2-bt-timings;</entry> |
| <entry><structfield>bt</structfield></entry> |
| <entry>Timings defined by BT.656/1120 specifications</entry> |
| </row> |
| <row> |
| <entry></entry> |
| <entry>__u32</entry> |
| <entry><structfield>reserved</structfield>[32]</entry> |
| <entry></entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| |
| <table pgwide="1" frame="none" id="dv-timing-types"> |
| <title>DV Timing types</title> |
| <tgroup cols="3"> |
| &cs-str; |
| <tbody valign="top"> |
| <row> |
| <entry>Timing type</entry> |
| <entry>value</entry> |
| <entry>Description</entry> |
| </row> |
| <row> |
| <entry></entry> |
| <entry></entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_BT_656_1120</entry> |
| <entry>0</entry> |
| <entry>BT.656/1120 timings</entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| <table pgwide="1" frame="none" id="dv-bt-standards"> |
| <title>DV BT Timing standards</title> |
| <tgroup cols="2"> |
| &cs-str; |
| <tbody valign="top"> |
| <row> |
| <entry>Timing standard</entry> |
| <entry>Description</entry> |
| </row> |
| <row> |
| <entry></entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_BT_STD_CEA861</entry> |
| <entry>The timings follow the CEA-861 Digital TV Profile standard</entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_BT_STD_DMT</entry> |
| <entry>The timings follow the VESA Discrete Monitor Timings standard</entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_BT_STD_CVT</entry> |
| <entry>The timings follow the VESA Coordinated Video Timings standard</entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_BT_STD_GTF</entry> |
| <entry>The timings follow the VESA Generalized Timings Formula standard</entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| <table pgwide="1" frame="none" id="dv-bt-flags"> |
| <title>DV BT Timing flags</title> |
| <tgroup cols="2"> |
| &cs-str; |
| <tbody valign="top"> |
| <row> |
| <entry>Flag</entry> |
| <entry>Description</entry> |
| </row> |
| <row> |
| <entry></entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_FL_REDUCED_BLANKING</entry> |
| <entry>CVT/GTF specific: the timings use reduced blanking (CVT) or the 'Secondary |
| GTF' curve (GTF). In both cases the horizontal and/or vertical blanking |
| intervals are reduced, allowing a higher resolution over the same |
| bandwidth. This is a read-only flag, applications must not set this. |
| </entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_FL_CAN_REDUCE_FPS</entry> |
| <entry>CEA-861 specific: set for CEA-861 formats with a framerate that is a multiple |
| of six. These formats can be optionally played at 1 / 1.001 speed to |
| be compatible with 60 Hz based standards such as NTSC and PAL-M that use a framerate of |
| 29.97 frames per second. If the transmitter can't generate such frequencies, then the |
| flag will also be cleared. This is a read-only flag, applications must not set this. |
| </entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_FL_REDUCED_FPS</entry> |
| <entry>CEA-861 specific: only valid for video transmitters, the flag is cleared |
| by receivers. It is also only valid for formats with the V4L2_DV_FL_CAN_REDUCE_FPS flag |
| set, for other formats the flag will be cleared by the driver. |
| |
| If the application sets this flag, then the pixelclock used to set up the transmitter is |
| divided by 1.001 to make it compatible with NTSC framerates. If the transmitter |
| can't generate such frequencies, then the flag will also be cleared. |
| </entry> |
| </row> |
| <row> |
| <entry>V4L2_DV_FL_HALF_LINE</entry> |
| <entry>Specific to interlaced formats: if set, then field 1 (aka the odd field) |
| is really one half-line longer and field 2 (aka the even field) is really one half-line |
| shorter, so each field has exactly the same number of half-lines. Whether half-lines can be |
| detected or used depends on the hardware. |
| </entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| </refsect1> |
| </refentry> |