VIDIOCQUERYCAP

VIDIOCQUERYCAP is a command used within the Video4Linux (V4L2) API, which is a Linux kernel interface supporting video capture and output devices. This command allows applications to query specific capabilities and properties of a device, such as a webcam, television tuner, or video capture card.

When invoked, VIDIOCQUERYCAP retrieves detailed information about the device, including the driver name, card description, bus information, driver version, and supported device capabilities. This information is essential for applications to understand the features and limitations of a video device, enabling proper configuration and operation.

The command is implemented as an ioctl (input/output control) system call within the Linux kernel, requiring a proper V4L2 device file (e.g., /dev/video0). The application must pass a pointer to a struct v4l2_capability structure, which the kernel fills with the device’s capabilities data.

Overall, VIDIOCQUERYCAP is a fundamental tool for device interrogation within the V4L2 framework, facilitating the development of multimedia applications and driver management by providing essential device metadata. Its use contributes to the interoperability and configurability of video devices on Linux systems.