FFmpeg
Cross-platform software to convert audio and video.
FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. It supports the most obscure ancient formats up to the cutting edge. No matter if they were designed by some standards committee, the community or a corporation.
FFmpeg provides: libavcodec, libavutil, libavformat, libavfilter, libavdevice, libswscale and libswresample which are used by many third party applications, higher level multimedia frameworks and video uploading sites on the internet. FFmpeg also includes the command line utilities: ffmpeg, ffserver, ffplay and ffprobe which are used by end users for transcoding, streaming and playback of multimedia content.