It’s a set of free decoders which significantly improves the playback picture quality, it’s widely used in modern media players.
The largest set of codecs, filters, and tools for audio/video decoding.
Powerful collection of codecs and filters for playing all formats of media files in the operating systems Windows 7/8/10.
Perhaps, it’s the most popular video codec of modernity, which initiated a large family of media container designed to compress video with acceptable quality. It’s the default format in almost every modern player.