1.. -*- coding: utf-8; mode: rst -*- 2 3.. _VIDIOC_ENUM_DV_TIMINGS: 4 5*********************************************************** 6ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS 7*********************************************************** 8 9Name 10==== 11 12VIDIOC_ENUM_DV_TIMINGS - VIDIOC_SUBDEV_ENUM_DV_TIMINGS - Enumerate supported Digital Video timings 13 14 15Synopsis 16======== 17 18.. c:function:: int ioctl( int fd, VIDIOC_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp ) 19 :name: VIDIOC_ENUM_DV_TIMINGS 20 21.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp ) 22 :name: VIDIOC_SUBDEV_ENUM_DV_TIMINGS 23 24 25Arguments 26========= 27 28``fd`` 29 File descriptor returned by :ref:`open() <func-open>`. 30 31``argp`` 32 Pointer to struct :c:type:`v4l2_enum_dv_timings`. 33 34 35Description 36=========== 37 38While some DV receivers or transmitters support a wide range of timings, 39others support only a limited number of timings. With this ioctl 40applications can enumerate a list of known supported timings. Call 41:ref:`VIDIOC_DV_TIMINGS_CAP` to check if it 42also supports other standards or even custom timings that are not in 43this list. 44 45To query the available timings, applications initialize the ``index`` 46field, set the ``pad`` field to 0, zero the reserved array of struct 47:c:type:`v4l2_enum_dv_timings` and call the 48``VIDIOC_ENUM_DV_TIMINGS`` ioctl on a video node with a pointer to this 49structure. Drivers fill the rest of the structure or return an ``EINVAL`` 50error code when the index is out of bounds. To enumerate all supported 51DV timings, applications shall begin at index zero, incrementing by one 52until the driver returns ``EINVAL``. 53 54.. note:: 55 56 Drivers may enumerate a different set of DV timings after 57 switching the video input or output. 58 59When implemented by the driver DV timings of subdevices can be queried 60by calling the ``VIDIOC_SUBDEV_ENUM_DV_TIMINGS`` ioctl directly on a 61subdevice node. The DV timings are specific to inputs (for DV receivers) 62or outputs (for DV transmitters), applications must specify the desired 63pad number in the struct 64:c:type:`v4l2_enum_dv_timings` ``pad`` field. 65Attempts to enumerate timings on a pad that doesn't support them will 66return an ``EINVAL`` error code. 67 68 69.. c:type:: v4l2_enum_dv_timings 70 71.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 72 73.. flat-table:: struct v4l2_enum_dv_timings 74 :header-rows: 0 75 :stub-columns: 0 76 :widths: 1 1 2 77 78 * - __u32 79 - ``index`` 80 - Number of the DV timings, set by the application. 81 * - __u32 82 - ``pad`` 83 - Pad number as reported by the media controller API. This field is 84 only used when operating on a subdevice node. When operating on a 85 video node applications must set this field to zero. 86 * - __u32 87 - ``reserved``\ [2] 88 - Reserved for future extensions. Drivers and applications must set 89 the array to zero. 90 * - struct :c:type:`v4l2_dv_timings` 91 - ``timings`` 92 - The timings. 93 94 95Return Value 96============ 97 98On success 0 is returned, on error -1 and the ``errno`` variable is set 99appropriately. The generic error codes are described at the 100:ref:`Generic Error Codes <gen-errors>` chapter. 101 102EINVAL 103 The struct :c:type:`v4l2_enum_dv_timings` 104 ``index`` is out of bounds or the ``pad`` number is invalid. 105 106ENODATA 107 Digital video presets are not supported for this input or output. 108