FFDShow Multi-Format Decoder

FFDShow is a Multi-Format Decoder filter with major Post Processing capabilities. It allows you to decode DIVX (all versions), XVID, MPEG-1, MPEG-2, MPEG-4, some of the WMV formats, Theora, VP3, Motion JPEG, HuffYUV, Sorenson 3, MP3, AC3, DTS, AAC, and more formats are being added on a regular basis. It also acts as a VERY strong post-processing engine that can work on the mentioned formats and on RAW audio/video (such as decoded from DVD content). It can enhance your image/audio by DeInterlacing, Sharpening, Noise Reduction, Scaling, and it's only getting more powerful with each version. It is currently the most highly recommended filter for use with DIVX/XVID playback.

FFDShow is very "Conflict Friendly". You can easily configure which formats you want it to play and it overrides any previous decoders assigned to these formats, all very cleanly.

A fork (FFDShow Tryouts) with updated decoders and fixes can be found on SourceForge.
The original ffdshow home page can be found here.