VidNumerator

This is a tiny library that uses syscalls to efficiently determine which /dev/videoN devices are webcams and which are the additional metadata control handles. The list of strings returned are the full filepaths to valid devices.

Important

In order for this library to work properly, the executing user must have either root or video group privileges

Technical Details

The library works by:

1. Scanning /dev for files matching the pattern video*
2. Using the VIDIOC_QUERYCAP ioctl to check if each device is a video capture device
3. Filtering out non-capture devices (like metadata control handles)

The core functionality is implemented through direct syscalls to the Linux kernel's V4L2 (Video4Linux2) API. The library uses the VIDIOC_QUERYCAP ioctl command to query device capabilities and determine if a device supports video capture.

Usage

devices, err := vidnumerator.EnumeratedVideoDevices()
if err != nil {
    // handle error
}
// devices will contain paths like "/dev/video0", "/dev/video2", etc.

Implementation Notes

• Uses direct syscalls via golang.org/x/sys/unix
• Implements custom ioctl constants for V4L2 device querying
• Checks for specific device capabilities (0x4200001) to identify capture devices