有很多東西可從http://www.winavi.com/codec.htm下載:

If you have any problem about play media file with your Windows media player, just reference:
http://www.moviecodec.com
http://www.dvdrhelp.com
http://www.doom9.org
You can download the following free support applications to convert additional file formats with WinAVI Video Converter.
Note: These applications are not required to use WinAVI Video Converter.

Microsoft DirectX
With DirectX, you can convert ASF file(s) to AVI file. WinAVI Video Converter needs DirectX 8.1 or later.
Microsoft Windows Media Format 9 Runtime
With Media Format 9, you can convert ASF file(s) to AVI file.
Quick Time
With QuickTime, you can convert MOV/MP4 file(s) to AVI file. WinAVI Video Converter needs QuickTime 6.0 or later.
RealOne player
With RealOne Player, you can convert Real Video/Audio file(s) to AVI/DVD file.
Recommend compatible MPEG/DVD codec:
If you have any problems with MPG/DVD to other format, you should download this compatible MPEG/DVD codec and unzip them to "Filter" sub-directory in the directory WinAVI installed, then you will convert MPG/DVD to other format correctly.
Real Video SDK to produce RM files:
If you want to convert any format to RM, you should download this RM SDK and unzip them to the directory WinAVI installed, then you will convert anything to RM format correctly.