>Can you say something about the question of whether M-JPEG supports a 
>soundtrack?  It's not clear from the specs if it does.

M-JPEG the codec format only has to do with video. Common file formats that 
wrap M-JPEG compressed video frames like AVI or QuickTime do have audio 
streams too.

A MPEG video stream is video only, although a MPEG system stream (what we 
think of as a MPEG file) is a combination of the MPEG video stream and 
audio streams.

DV format actually intertwines video and audio pretty tightly. Native DV 
format is actually the format used to write blocks on a DV tape, which is 
why things are so intertwined. It's common for editing programs to extract 
out the audio part and put it in a separate stream, either as a pre-edit 
step or else while transferring the DV data into a platform local wrapping 
file format, like AVI or QuickTime.

- Jan