ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT &manvol; VIDIOC_G_INPUT VIDIOC_S_INPUT Query or select the current video input int ioctl int fd int request int *argp fd &fd; request VIDIOC_G_INPUT, VIDIOC_S_INPUT argp To query the current video input applications call the VIDIOC_G_INPUT ioctl with a pointer to an integer where the driver stores the number of the input, as in the &v4l2-input; index field. This ioctl will fail only when there are no video inputs, returning EINVAL. To select a video input applications store the number of the desired input in an integer and call the VIDIOC_S_INPUT ioctl with a pointer to this integer. Side effects are possible. For example inputs may support different video standards, so the driver may implicitly switch the current standard. It is good practice to select an input before querying or negotiating any other parameters. Information about video inputs is available using the &VIDIOC-ENUMINPUT; ioctl. &return-value; EINVAL The number of the video input is out of bounds.