K-Lite Codec Pack is a collection of DirectShow filters, VFW/ACM codecs, and tools. Codecs and DirectShow filters are used for encoding and decoding audio and video formats.
K-Lite Codec Pack is available in Basic, Standard, Full, and Mega variants. Mega Codec Pack is the largest of all codec packs, featuring additional codecs, audio parsers, source filters, and subtitle filters. It also packs Codec Tweak Tool, MediaInfo Lite, GraphStudioNext, VobSubStrip, Haali Muxer, and FourCC Changer tools.
Very good, been using for years.
It solves multi format playing issues.
The update downloades the "basic" version of the codec, not the "mega" version!