ioctl VIDIOC_DV_TIMINGS_CAP, VIDIOC_SUBDEV_DV_TIMINGS_CAP
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## Name

VIDIOC_DV_TIMINGS_CAP, VIDIOC_SUBDEV_DV_TIMINGS_CAP — The capabilities of the Digital Video receiver/transmitter

## Synopsis

`int ioctl(` | int fd,
| int request,
| struct v4l2_dv_timings_cap *argp`)`;

## Arguments

`fd`

  File descriptor returned by `open()`.

`request`

  VIDIOC_DV_TIMINGS_CAP, VIDIOC_SUBDEV_DV_TIMINGS_CAP

`argp`

## Description

### Experimental

This is an experimental interface and may change in the future.

To query the capabilities of the DV receiver/transmitter applications can call the `VIDIOC_DV_TIMINGS_CAP` ioctl on a video node and the driver will fill in the structure. Note that drivers may return different values after switching the video input or output.

When implemented by the driver DV capabilities of subdevices can be queried by calling the `VIDIOC_SUBDEV_DV_TIMINGS_CAP` ioctl directly on a subdevice node. The capabilities are specific to inputs (for DV receivers) or outputs (for DV transmitters), applications must specify the desired pad number in the struct v4l2_dv_timings_cap `pad` field. Attempts to query capabilities on a pad that doesn't support them will return an EINVAL error code.

Table A.21. struct v4l2_bt_timings_cap

__u32 | `min_width` | Minimum width of the active video in pixels.
__u32 | `max_width` | Maximum width of the active video in pixels.
__u32 | `min_height` | Minimum height of the active video in lines.
__u32 | `max_height` | Maximum height of the active video in lines.
__u64 | `min_pixelclock` | Minimum pixelclock frequency in Hz.
__u64 | `max_pixelclock` | Maximum pixelclock frequency in Hz.
__u32 | `standards` | The video standard(s) supported by the hardware. See Table A.60, “DV BT Timing standards” for a list of standards.
__u32 | `capabilities` | Several flags giving more information about the capabilities. See Table A.23, “DV BT Timing capabilities” for a description of the flags.
__u32 | `reserved`[16] | Reserved for future extensions. Drivers must set the array to zero.

Table A.22. struct v4l2_dv_timings_cap

__u32 | `type` | Type of DV timings as listed in Table A.59, “DV Timing types”. |
__u32 | `pad` | Pad number as reported by the media controller API. This field is only used when operating on a subdevice node. When operating on a video node applications must set this field to zero. |
__u32 | `reserved`[2] | Reserved for future extensions. Drivers must set the array to zero. |
union | `` |  |
| struct v4l2_bt_timings_cap | `bt` | BT.656/1120 timings capabilities of the hardware.
| __u32 | `raw_data`[32] |

Table A.23. DV BT Timing capabilities

Flag | Description
V4L2_DV_BT_CAP_INTERLACED | Interlaced formats are supported.
V4L2_DV_BT_CAP_PROGRESSIVE | Progressive formats are supported.
V4L2_DV_BT_CAP_REDUCED_BLANKING | CVT/GTF specific: the timings can make use of reduced blanking (CVT) or the 'Secondary GTF' curve (GTF).
V4L2_DV_BT_CAP_CUSTOM | Can support non-standard timings, i.e. timings not belonging to the standards set in the `standards` field.

## 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 Generic Error Codes chapter.

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