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+.. -*- 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.