mirror of https://gitee.com/openkylin/linux.git
313 lines
11 KiB
ReStructuredText
313 lines
11 KiB
ReStructuredText
.. Permission is granted to copy, distribute and/or modify this
|
|
.. document under the terms of the GNU Free Documentation License,
|
|
.. Version 1.1 or any later version published by the Free Software
|
|
.. Foundation, with no Invariant Sections, no Front-Cover Texts
|
|
.. and no Back-Cover Texts. A copy of the license is included at
|
|
.. Documentation/media/uapi/fdl-appendix.rst.
|
|
..
|
|
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
|
|
|
|
.. _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
|
|
========
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_G_DV_TIMINGS, struct v4l2_dv_timings *argp )
|
|
:name: VIDIOC_G_DV_TIMINGS
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_S_DV_TIMINGS, struct v4l2_dv_timings *argp )
|
|
:name: VIDIOC_S_DV_TIMINGS
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_DV_TIMINGS, struct v4l2_dv_timings *argp )
|
|
:name: VIDIOC_SUBDEV_G_DV_TIMINGS
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_DV_TIMINGS, struct v4l2_dv_timings *argp )
|
|
:name: VIDIOC_SUBDEV_S_DV_TIMINGS
|
|
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :ref:`open() <func-open>`.
|
|
|
|
``argp``
|
|
Pointer to struct :c:type:`v4l2_dv_timings`.
|
|
|
|
|
|
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
|
|
:c:type:`v4l2_dv_timings`. These ioctls take a
|
|
pointer to the struct :c:type:`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.
|
|
|
|
|
|
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
|
|
|
|
.. c:type:: v4l2_bt_timings
|
|
|
|
.. flat-table:: struct v4l2_bt_timings
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 1 1 2
|
|
|
|
* - __u32
|
|
- ``width``
|
|
- Width of the active video in pixels.
|
|
* - __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.
|
|
* - __u32
|
|
- ``interlaced``
|
|
- Progressive (``V4L2_DV_PROGRESSIVE``) or interlaced (``V4L2_DV_INTERLACED``).
|
|
* - __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.
|
|
* - __u64
|
|
- ``pixelclock``
|
|
- Pixel clock in Hz. Ex. 74.25MHz->74250000
|
|
* - __u32
|
|
- ``hfrontporch``
|
|
- Horizontal front porch in pixels
|
|
* - __u32
|
|
- ``hsync``
|
|
- Horizontal sync length in pixels
|
|
* - __u32
|
|
- ``hbackporch``
|
|
- Horizontal back porch in pixels
|
|
* - __u32
|
|
- ``vfrontporch``
|
|
- Vertical front porch in lines. For interlaced formats this refers
|
|
to the odd field (aka field 1).
|
|
* - __u32
|
|
- ``vsync``
|
|
- Vertical sync length in lines. For interlaced formats this refers
|
|
to the odd field (aka field 1).
|
|
* - __u32
|
|
- ``vbackporch``
|
|
- Vertical back porch in lines. For interlaced formats this refers
|
|
to the odd field (aka field 1).
|
|
* - __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.
|
|
* - __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.
|
|
* - __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.
|
|
* - __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.
|
|
* - __u32
|
|
- ``flags``
|
|
- Several flags giving more information about the format. See
|
|
:ref:`dv-bt-flags` for a description of the flags.
|
|
* - struct :c:type:`v4l2_fract`
|
|
- ``picture_aspect``
|
|
- The picture aspect if the pixels are not square. Only valid if the
|
|
``V4L2_DV_FL_HAS_PICTURE_ASPECT`` flag is set.
|
|
* - __u8
|
|
- ``cea861_vic``
|
|
- The Video Identification Code according to the CEA-861 standard.
|
|
Only valid if the ``V4L2_DV_FL_HAS_CEA861_VIC`` flag is set.
|
|
* - __u8
|
|
- ``hdmi_vic``
|
|
- The Video Identification Code according to the HDMI standard.
|
|
Only valid if the ``V4L2_DV_FL_HAS_HDMI_VIC`` flag is set.
|
|
* - __u8
|
|
- ``reserved[46]``
|
|
- Reserved for future extensions. Drivers and applications must set
|
|
the array to zero.
|
|
|
|
|
|
.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{7.0cm}|p{3.5cm}|
|
|
|
|
.. c:type:: v4l2_dv_timings
|
|
|
|
.. flat-table:: struct v4l2_dv_timings
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 1 1 2
|
|
|
|
* - __u32
|
|
- ``type``
|
|
- Type of DV timings as listed in :ref:`dv-timing-types`.
|
|
* - union {
|
|
- (anonymous)
|
|
* - struct :c:type:`v4l2_bt_timings`
|
|
- ``bt``
|
|
- Timings defined by BT.656/1120 specifications
|
|
* - __u32
|
|
- ``reserved``\ [32]
|
|
-
|
|
* - }
|
|
-
|
|
|
|
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
|
|
|
|
.. _dv-timing-types:
|
|
|
|
.. flat-table:: DV Timing types
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 1 1 2
|
|
|
|
* - Timing type
|
|
- value
|
|
- Description
|
|
* -
|
|
-
|
|
-
|
|
* - ``V4L2_DV_BT_656_1120``
|
|
- 0
|
|
- BT.656/1120 timings
|
|
|
|
.. tabularcolumns:: |p{4.5cm}|p{12.8cm}|
|
|
|
|
.. _dv-bt-standards:
|
|
|
|
.. flat-table:: DV BT Timing standards
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
|
|
* - Timing standard
|
|
- Description
|
|
* - ``V4L2_DV_BT_STD_CEA861``
|
|
- The timings follow the CEA-861 Digital TV Profile standard
|
|
* - ``V4L2_DV_BT_STD_DMT``
|
|
- The timings follow the VESA Discrete Monitor Timings standard
|
|
* - ``V4L2_DV_BT_STD_CVT``
|
|
- The timings follow the VESA Coordinated Video Timings standard
|
|
* - ``V4L2_DV_BT_STD_GTF``
|
|
- The timings follow the VESA Generalized Timings Formula standard
|
|
* - ``V4L2_DV_BT_STD_SDI``
|
|
- The timings follow the SDI Timings standard.
|
|
There are no horizontal syncs/porches at all in this format.
|
|
Total blanking timings must be set in hsync or vsync fields only.
|
|
|
|
.. tabularcolumns:: |p{7.0cm}|p{10.5cm}|
|
|
|
|
.. _dv-bt-flags:
|
|
|
|
.. flat-table:: DV BT Timing flags
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
|
|
* - Flag
|
|
- Description
|
|
* - ``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.
|
|
* - ``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.
|
|
* - ``V4L2_DV_FL_REDUCED_FPS``
|
|
- CEA-861 specific: only valid for video transmitters or video
|
|
receivers that have the ``V4L2_DV_FL_CAN_DETECT_REDUCED_FPS``
|
|
set. This flag is cleared otherwise. 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 for a transmitter, 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 be cleared.
|
|
|
|
If a video receiver detects that the format uses a reduced framerate,
|
|
then it will set this flag to signal this to the application.
|
|
* - ``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.
|
|
* - ``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.
|
|
* - ``V4L2_DV_FL_FIRST_FIELD_EXTRA_LINE``
|
|
- Some formats like SMPTE-125M have an interlaced signal with a odd
|
|
total height. For these formats, if this flag is set, the first
|
|
field has the extra line. Else, it is the second field.
|
|
* - ``V4L2_DV_FL_HAS_PICTURE_ASPECT``
|
|
- If set, then the picture_aspect field is valid. Otherwise assume that
|
|
the pixels are square, so the picture aspect ratio is the same as the
|
|
width to height ratio.
|
|
* - ``V4L2_DV_FL_HAS_CEA861_VIC``
|
|
- If set, then the cea861_vic field is valid and contains the Video
|
|
Identification Code as per the CEA-861 standard.
|
|
* - ``V4L2_DV_FL_HAS_HDMI_VIC``
|
|
- If set, then the hdmi_vic field is valid and contains the Video
|
|
Identification Code as per the HDMI standard (HDMI Vendor Specific
|
|
InfoFrame).
|
|
* - ``V4L2_DV_FL_CAN_DETECT_REDUCED_FPS``
|
|
- CEA-861 specific: only valid for video receivers, the flag is
|
|
cleared by transmitters.
|
|
If set, then the hardware can detect the difference between
|
|
regular framerates and framerates reduced by 1000/1001. E.g.:
|
|
60 vs 59.94 Hz, 30 vs 29.97 Hz or 24 vs 23.976 Hz.
|