libv4l1
libv4l1 is a user-space library that provides compatibility for applications written to the Video4Linux version 1 (V4L1) API when interfacing with video devices on Linux. It implements a subset of the V4L1 interface in terms of the modern V4L2 kernel API, enabling legacy software to work with current drivers without modification.
The library operates as a translation layer: when a V4L1 application issues ioctls, reads, or memory-mapped
libv4l1 is distributed as part of certain Linux distributions alongside v4l-utils or as a standalone library.