| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _VIDIOC_G_DV_TIMINGS: |
| |
| ********************************************** |
| ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS |
| ********************************************** |
| |
| Name |
| ==== |
| |
| VIDIOC_G_DV_TIMINGS - VIDIOC_S_DV_TIMINGS - VIDIOC_SUBDEV_G_DV_TIMINGS - VIDIOC_SUBDEV_S_DV_TIMINGS - Get or set DV timings for input or output |
| |
| |
| Synopsis |
| ======== |
| |
| .. cpp:function:: int ioctl( int fd, int request, struct v4l2_dv_timings *argp ) |
| |
| |
| Arguments |
| ========= |
| |
| ``fd`` |
| File descriptor returned by :ref:`open() <func-open>`. |
| |
| ``request`` |
| VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS, |
| VIDIOC_SUBDEV_G_DV_TIMINGS, VIDIOC_SUBDEV_S_DV_TIMINGS |
| |
| ``argp`` |
| |
| |
| Description |
| =========== |
| |
| To set DV timings for the input or output, applications use the |
| :ref:`VIDIOC_S_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl and to get the current timings, |
| applications use the :ref:`VIDIOC_G_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl. The detailed timing |
| information is filled in using the structure struct |
| :ref:`v4l2_dv_timings <v4l2-dv-timings>`. These ioctls take a |
| pointer to the struct :ref:`v4l2_dv_timings <v4l2-dv-timings>` |
| structure as argument. If the ioctl is not supported or the timing |
| values are not correct, the driver returns ``EINVAL`` error code. |
| |
| The ``linux/v4l2-dv-timings.h`` header can be used to get the timings of |
| the formats in the :ref:`cea861` and :ref:`vesadmt` standards. If |
| the current input or output does not support DV timings (e.g. if |
| :ref:`VIDIOC_ENUMINPUT` does not set the |
| ``V4L2_IN_CAP_DV_TIMINGS`` flag), then ``ENODATA`` error code is returned. |
| |
| |
| Return Value |
| ============ |
| |
| On success 0 is returned, on error -1 and the ``errno`` variable is set |
| appropriately. The generic error codes are described at the |
| :ref:`Generic Error Codes <gen-errors>` chapter. |
| |
| EINVAL |
| This ioctl is not supported, or the :ref:`VIDIOC_S_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` |
| parameter was unsuitable. |
| |
| ENODATA |
| Digital video timings are not supported for this input or output. |
| |
| EBUSY |
| The device is busy and therefore can not change the timings. |
| |
| |
| .. _v4l2-bt-timings: |
| |
| .. flat-table:: struct v4l2_bt_timings |
| :header-rows: 0 |
| :stub-columns: 0 |
| :widths: 1 1 2 |
| |
| |
| - .. row 1 |
| |
| - __u32 |
| |
| - ``width`` |
| |
| - Width of the active video in pixels. |
| |
| - .. row 2 |
| |
| - __u32 |
| |
| - ``height`` |
| |
| - Height of the active video frame in lines. So for interlaced |
| formats the height of the active video in each field is |
| ``height``/2. |
| |
| - .. row 3 |
| |
| - __u32 |
| |
| - ``interlaced`` |
| |
| - Progressive (``V4L2_DV_PROGRESSIVE``) or interlaced (``V4L2_DV_INTERLACED``). |
| |
| - .. row 4 |
| |
| - __u32 |
| |
| - ``polarities`` |
| |
| - 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. |
| |
| - .. row 5 |
| |
| - __u64 |
| |
| - ``pixelclock`` |
| |
| - Pixel clock in Hz. Ex. 74.25MHz->74250000 |
| |
| - .. row 6 |
| |
| - __u32 |
| |
| - ``hfrontporch`` |
| |
| - Horizontal front porch in pixels |
| |
| - .. row 7 |
| |
| - __u32 |
| |
| - ``hsync`` |
| |
| - Horizontal sync length in pixels |
| |
| - .. row 8 |
| |
| - __u32 |
| |
| - ``hbackporch`` |
| |
| - Horizontal back porch in pixels |
| |
| - .. row 9 |
| |
| - __u32 |
| |
| - ``vfrontporch`` |
| |
| - Vertical front porch in lines. For interlaced formats this refers |
| to the odd field (aka field 1). |
| |
| - .. row 10 |
| |
| - __u32 |
| |
| - ``vsync`` |
| |
| - Vertical sync length in lines. For interlaced formats this refers |
| to the odd field (aka field 1). |
| |
| - .. row 11 |
| |
| - __u32 |
| |
| - ``vbackporch`` |
| |
| - Vertical back porch in lines. For interlaced formats this refers |
| to the odd field (aka field 1). |
| |
| - .. row 12 |
| |
| - __u32 |
| |
| - ``il_vfrontporch`` |
| |
| - Vertical front porch in lines for the even field (aka field 2) of |
| interlaced field formats. Must be 0 for progressive formats. |
| |
| - .. row 13 |
| |
| - __u32 |
| |
| - ``il_vsync`` |
| |
| - Vertical sync length in lines for the even field (aka field 2) of |
| interlaced field formats. Must be 0 for progressive formats. |
| |
| - .. row 14 |
| |
| - __u32 |
| |
| - ``il_vbackporch`` |
| |
| - Vertical back porch in lines for the even field (aka field 2) of |
| interlaced field formats. Must be 0 for progressive formats. |
| |
| - .. row 15 |
| |
| - __u32 |
| |
| - ``standards`` |
| |
| - The video standard(s) this format belongs to. This will be filled |
| in by the driver. Applications must set this to 0. See |
| :ref:`dv-bt-standards` for a list of standards. |
| |
| - .. row 16 |
| |
| - __u32 |
| |
| - ``flags`` |
| |
| - Several flags giving more information about the format. See |
| :ref:`dv-bt-flags` for a description of the flags. |
| |
| |
| |
| .. _v4l2-dv-timings: |
| |
| .. flat-table:: struct v4l2_dv_timings |
| :header-rows: 0 |
| :stub-columns: 0 |
| :widths: 1 1 2 1 |
| |
| |
| - .. row 1 |
| |
| - __u32 |
| |
| - ``type`` |
| |
| - |
| - Type of DV timings as listed in :ref:`dv-timing-types`. |
| |
| - .. row 2 |
| |
| - union |
| |
| - |
| - |
| |
| - .. row 3 |
| |
| - |
| - struct :ref:`v4l2_bt_timings <v4l2-bt-timings>` |
| |
| - ``bt`` |
| |
| - Timings defined by BT.656/1120 specifications |
| |
| - .. row 4 |
| |
| - |
| - __u32 |
| |
| - ``reserved``\ \[32\] |
| |
| - |
| |
| |
| |
| .. _dv-timing-types: |
| |
| .. flat-table:: DV Timing types |
| :header-rows: 0 |
| :stub-columns: 0 |
| :widths: 1 1 2 |
| |
| |
| - .. row 1 |
| |
| - Timing type |
| |
| - value |
| |
| - Description |
| |
| - .. row 2 |
| |
| - |
| - |
| - |
| |
| - .. row 3 |
| |
| - ``V4L2_DV_BT_656_1120`` |
| |
| - 0 |
| |
| - BT.656/1120 timings |
| |
| |
| |
| .. _dv-bt-standards: |
| |
| .. flat-table:: DV BT Timing standards |
| :header-rows: 0 |
| :stub-columns: 0 |
| |
| |
| - .. row 1 |
| |
| - Timing standard |
| |
| - Description |
| |
| - .. row 2 |
| |
| - |
| - |
| |
| - .. row 3 |
| |
| - ``V4L2_DV_BT_STD_CEA861`` |
| |
| - The timings follow the CEA-861 Digital TV Profile standard |
| |
| - .. row 4 |
| |
| - ``V4L2_DV_BT_STD_DMT`` |
| |
| - The timings follow the VESA Discrete Monitor Timings standard |
| |
| - .. row 5 |
| |
| - ``V4L2_DV_BT_STD_CVT`` |
| |
| - The timings follow the VESA Coordinated Video Timings standard |
| |
| - .. row 6 |
| |
| - ``V4L2_DV_BT_STD_GTF`` |
| |
| - The timings follow the VESA Generalized Timings Formula standard |
| |
| |
| |
| .. _dv-bt-flags: |
| |
| .. flat-table:: DV BT Timing flags |
| :header-rows: 0 |
| :stub-columns: 0 |
| |
| |
| - .. row 1 |
| |
| - Flag |
| |
| - Description |
| |
| - .. row 2 |
| |
| - |
| - |
| |
| - .. row 3 |
| |
| - ``V4L2_DV_FL_REDUCED_BLANKING`` |
| |
| - 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. |
| |
| - .. row 4 |
| |
| - ``V4L2_DV_FL_CAN_REDUCE_FPS`` |
| |
| - 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. |
| |
| - .. row 5 |
| |
| - ``V4L2_DV_FL_REDUCED_FPS`` |
| |
| - 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. |
| |
| - .. row 6 |
| |
| - ``V4L2_DV_FL_HALF_LINE`` |
| |
| - Specific to interlaced formats: if set, then the vertical |
| frontporch of field 1 (aka the odd field) is really one half-line |
| longer and the vertical backporch of 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. |
| |
| - .. row 7 |
| |
| - ``V4L2_DV_FL_IS_CE_VIDEO`` |
| |
| - If set, then this is a Consumer Electronics (CE) video format. |
| Such formats differ from other formats (commonly called IT |
| formats) in that if R'G'B' encoding is used then by default the |
| R'G'B' values use limited range (i.e. 16-235) as opposed to full |
| range (i.e. 0-255). All formats defined in CEA-861 except for the |
| 640x480p59.94 format are CE formats. |