VIDIOCSBUF

VIDIOCSBUF is an ioctl command from the legacy Video for Linux (V4L1) API used to configure the video buffer pool of a capture or playback device. It is defined in the linux/videodev.h header and works by passing a pointer to a struct (commonly referred to as a video_buffer) to the device driver. The driver then uses the information to allocate and manage a set of buffers that hold video frames during streaming.

The details of the struct passed to VIDIOCSBUF are implementation dependent, but the command generally conveys parameters related to the buffer pool, such as the number of buffers and their size. The exact behavior can vary between drivers, with some devices using the kernel's videobuf memory model to manage these buffers and others performing allocation in different ways. Because this ioctl is part of the older V4L1 interface, its behavior and availability are not guaranteed on modern systems.

Compatibility and modernization: VIDIOCSBUF belongs to the older V4L1 API, which has largely been superseded by the Video4Linux2 (V4L2) interface. Modern applications and drivers typically use V4L2 ioctls such as VIDIOC_REQBUFS, VIDIOC_QBUF, and VIDIOC_DQBUF for robust and standardized streaming. Some drivers and systems retain partial V4L1 compatibility for legacy software, but new development is generally directed at V4L2.

See also: Video for Linux, V4L1 ioctls, V4L2 ioctls, VIDIOC_REQBUFS, VIDIOC_QBUF, VIDIOC_DQBUF.