1*4882a593Smuzhiyun.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2*4882a593Smuzhiyun 3*4882a593Smuzhiyun.. _dv-timings: 4*4882a593Smuzhiyun 5*4882a593Smuzhiyun************************** 6*4882a593SmuzhiyunDigital Video (DV) Timings 7*4882a593Smuzhiyun************************** 8*4882a593Smuzhiyun 9*4882a593SmuzhiyunThe video standards discussed so far have been dealing with Analog TV 10*4882a593Smuzhiyunand the corresponding video timings. Today there are many more different 11*4882a593Smuzhiyunhardware interfaces such as High Definition TV interfaces (HDMI), VGA, 12*4882a593SmuzhiyunDVI connectors etc., that carry video signals and there is a need to 13*4882a593Smuzhiyunextend the API to select the video timings for these interfaces. Since 14*4882a593Smuzhiyunit is not possible to extend the :ref:`v4l2_std_id <v4l2-std-id>` 15*4882a593Smuzhiyundue to the limited bits available, a new set of ioctls was added to 16*4882a593Smuzhiyunset/get video timings at the input and output. 17*4882a593Smuzhiyun 18*4882a593SmuzhiyunThese ioctls deal with the detailed digital video timings that define 19*4882a593Smuzhiyuneach video format. This includes parameters such as the active video 20*4882a593Smuzhiyunwidth and height, signal polarities, frontporches, backporches, sync 21*4882a593Smuzhiyunwidths etc. The ``linux/v4l2-dv-timings.h`` header can be used to get 22*4882a593Smuzhiyunthe timings of the formats in the :ref:`cea861` and :ref:`vesadmt` 23*4882a593Smuzhiyunstandards. 24*4882a593Smuzhiyun 25*4882a593SmuzhiyunTo enumerate and query the attributes of the DV timings supported by a 26*4882a593Smuzhiyundevice applications use the 27*4882a593Smuzhiyun:ref:`VIDIOC_ENUM_DV_TIMINGS` and 28*4882a593Smuzhiyun:ref:`VIDIOC_DV_TIMINGS_CAP` ioctls. To set 29*4882a593SmuzhiyunDV timings for the device applications use the 30*4882a593Smuzhiyun:ref:`VIDIOC_S_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl and to get 31*4882a593Smuzhiyuncurrent DV timings they use the 32*4882a593Smuzhiyun:ref:`VIDIOC_G_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl. To detect 33*4882a593Smuzhiyunthe DV timings as seen by the video receiver applications use the 34*4882a593Smuzhiyun:ref:`VIDIOC_QUERY_DV_TIMINGS` ioctl. 35*4882a593Smuzhiyun 36*4882a593SmuzhiyunApplications can make use of the :ref:`input-capabilities` and 37*4882a593Smuzhiyun:ref:`output-capabilities` flags to determine whether the digital 38*4882a593Smuzhiyunvideo ioctls can be used with the given input or output. 39