audio codecs?

just a quick question, i downloaded a movie from a bt, and tried playing it in quicktime. the video plays but no audio. so i downloaded divx for mac and tried it and still no audio. can anyone recommend a "universal" codec that can play a wide range of audio files with movies?

Thanks

Try here: http://www.mactcp.org.nz/quicktime/
Bottom of page, has instructions in readme file.