VIDIOC_ENUMOUTPUT — Enumerate video outputs
|struct v4l2_output *argp|
File descriptor returned by
To query the attributes of a video outputs applications
index field of struct v4l2_output
and call the
VIDIOC_ENUMOUTPUT ioctl with a
pointer to this structure. Drivers fill the rest of the structure or
return an EINVAL error code when the index is out of bounds. To enumerate all
outputs applications shall begin at index zero, incrementing by one
until the driver returns EINVAL.
Table A.39. struct v4l2_output
|__u32||Identifies the output, set by the application.|
|__u8||Name of the video output, a NUL-terminated ASCII string, for example: "Vout". This information is intended for the user, preferably the connector label on the device itself.|
|__u32||Type of the output, see Table A.40, “Output Type”.|
Drivers can enumerate up to 32 video and audio outputs. This field shows which audio outputs were selectable as the current output if this was the currently selected video output. It is a bit mask. The LSB corresponds to audio output 0, the MSB to output 31. Any number of bits can be set, or none.
When the driver does not enumerate audio outputs no bits must be set. Applications shall not interpret this as lack of audio support. Drivers may automatically select audio outputs without enumerating them.
For details on audio outputs and how to select the current output see the section called “Audio Inputs and Outputs”.
|__u32||Output devices can have zero or more RF modulators.
When the |
|v4l2_std_id||Every video output supports one or more different video standards. This field is a set of all supported standards. For details on video standards and how to switch see the section called “Video Standards”.|
|__u32||This field provides capabilities for the output. See Table A.41, “Output capabilities” for flags.|
|__u32||Reserved for future extensions. Drivers must set the array to zero.|
Table A.40. Output Type
|1||This output is an analog TV modulator.|
|2||Analog baseband output, for example Composite / CVBS, S-Video, RGB.|
Table A.41. Output capabilities
|0x00000002||This output supports setting video timings by using VIDIOC_S_DV_TIMINGS.|
|0x00000004||This output supports setting the TV standard by using VIDIOC_S_STD.|