VIDIOC_ENUMINPUT - Enumerate video inputs
To query the attributes of a video input applications initialize the index field of struct v4l2_input and call the ioctl VIDIOC_ENUMINPUT 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 inputs applications shall begin at index zero, incrementing by one until the driver returns EINVAL.
| __u32 | index | Identifies the input, set by the application. |
| __u8 | name[32] | Name of the video input, a NUL-terminated ASCII string, for example: “Vin (Composite 2)”. This information is intended for the user, preferably the connector label on the device itself. |
| __u32 | type | Type of the input, see Input Types. |
| __u32 | audioset | Drivers can enumerate up to 32 video and audio inputs. This field shows which audio inputs were selectable as audio source if this was the currently selected video input. It is a bit mask. The LSB corresponds to audio input 0, the MSB to input 31. Any number of bits can be set, or none. When the driver does not enumerate audio inputs no bits must be set. Applications shall not interpret this as lack of audio support. Some drivers automatically select audio sources and do not enumerate them since there is no choice anyway. For details on audio inputs and how to select the current input see Audio Inputs and Outputs. |
| __u32 | tuner | Capture devices can have zero or more tuners (RF demodulators). When the type is set to V4L2_INPUT_TYPE_TUNER this is an RF connector and this field identifies the tuner. It corresponds to struct v4l2_tuner field index. For details on tuners see Tuners and Modulators. |
| v4l2_std_id | std | Every video input 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 Video Standards. |
| __u32 | status | This field provides status information about the input. See Input Status Flags for flags. With the exception of the sensor orientation bits status is only valid when this is the current input. |
| __u32 | capabilities | This field provides capabilities for the input. See Input capabilities for flags. |
| __u32 | reserved[3] | Reserved for future extensions. Drivers must set the array to zero. |
| V4L2_INPUT_TYPE_TUNER | 1 | This input uses a tuner (RF demodulator). |
| V4L2_INPUT_TYPE_CAMERA | 2 | Analog baseband input, for example CVBS / Composite Video, S-Video, RGB. |
| V4L2_INPUT_TYPE_TOUCH | 3 | This input is a touch device for capturing raw touch data. |
| General | ||
| V4L2_IN_ST_NO_POWER | 0x00000001 | Attached device is off. |
| V4L2_IN_ST_NO_SIGNAL | 0x00000002 | |
| V4L2_IN_ST_NO_COLOR | 0x00000004 | The hardware supports color decoding, but does not detect color modulation in the signal. |
| Sensor Orientation | ||
| V4L2_IN_ST_HFLIP | 0x00000010 | The input is connected to a device that produces a signal that is flipped horizontally and does not correct this before passing the signal to userspace. |
| V4L2_IN_ST_VFLIP | 0x00000020 | The input is connected to a device that produces a signal that is flipped vertically and does not correct this before passing the signal to userspace. .. note:: A 180 degree rotation is the same as HFLIP | VFLIP |
| Analog Video | ||
| V4L2_IN_ST_NO_H_LOCK | 0x00000100 | No horizontal sync lock. |
| V4L2_IN_ST_COLOR_KILL | 0x00000200 | A color killer circuit automatically disables color decoding when it detects no color modulation. When this flag is set the color killer is enabled and has shut off color decoding. |
| V4L2_IN_ST_NO_V_LOCK | 0x00000400 | No vertical sync lock. |
| V4L2_IN_ST_NO_STD_LOCK | 0x00000800 | No standard format lock in case of auto-detection format by the component. |
| Digital Video | ||
| V4L2_IN_ST_NO_SYNC | 0x00010000 | No synchronization lock. |
| V4L2_IN_ST_NO_EQU | 0x00020000 | No equalizer lock. |
| V4L2_IN_ST_NO_CARRIER | 0x00040000 | Carrier recovery failed. |
| VCR and Set-Top Box | ||
| V4L2_IN_ST_MACROVISION | 0x01000000 | Macrovision is an analog copy prevention system mangling the video signal to confuse video recorders. When this flag is set Macrovision has been detected. |
| V4L2_IN_ST_NO_ACCESS | 0x02000000 | Conditional access denied. |
| V4L2_IN_ST_VTR | 0x04000000 | VTR time constant. [?] |
| V4L2_IN_CAP_DV_TIMINGS | 0x00000002 | This input supports setting video timings by using VIDIOC_S_DV_TIMINGS. |
| V4L2_IN_CAP_STD | 0x00000004 | This input supports setting the TV standard by using VIDIOC_S_STD. |
| V4L2_IN_CAP_NATIVE_SIZE | 0x00000008 | This input supports setting the native size using the V4L2_SEL_TGT_NATIVE_SIZE selection target, see Common selection definitions. |
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.