diff options
Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst | 417 |
1 files changed, 417 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst b/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst new file mode 100644 index 000000000000..f7bf21f49092 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst @@ -0,0 +1,417 @@ +.. -*- 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. |