FFDShow MPEG-4 Video Decoder is a set of DirectShow filters and VFW codec for video compression, decompression and processing and audio compression and processing.
You can play almost any movie using ffdshow.
FFDShow MPEG-4 Video Decoder uses libavcodec from ffmpeg project or for video decompression (it can use xvid.dll installed with xvid codec too), postprocessing code from mplayer to enhance visual quality of low bitrate movies, and is based on original DirectShow filter from XviD, which is GPL'ed educational implementation of MPEG4 encoder.
FFDShow MPEG-4 Video Decoder is DirectShow and VFW codec for decoding/encoding many video and audio formats, including DivX and XviD movies using libavcodec, xvid and other opensourced libraries with a rich set of postprocessing filters.

FFDShow MPEG Video Decoder Features:
1. fast video decompression using optimized MMX, SSE and 3DNow! code
2. support for different codecs: XviD, all DivX versions, MS WMV, MPEG-1 and - MPEG-2
3. image postprocessing for higher playback quality
4. automatic quality control: automatically reduces postprocessing level when CPU load is high
5. hue, saturation and luminance correction
6. experimental sharpening filter
7. noising (of course if you want it)
8. presets
9. completely free software: ffdshow is distributed under GPL
10. support for various subtitle formats

The license of this software is Free, you can free download and free use this video converter software.