FFmpeg is a free and open-source software project that provides a complete, cross-platform solution for recording, converting, and streaming audio and video. It includes libavcodec, an audio/video codec library, and libavformat, an audio/video container mux and demux library. FFmpeg is widely used for a variety of tasks, including converting between different video and audio formats, transcoding video and audio for playback on different devices, and streaming audio and video over the internet. It is available for Linux, macOS, and Windows.