no audio converting MPEG1/MP3 to H.264 for iPod

[Dan Christensen]

My Sony Cybershot camera can take video clips in MPEG-1 format with
MP3 audio.  These clips play fine, e.g. using Quicktime on a Mac or
using mplayer under linux.  But when I try to convert to H.264 using
Quicktime Pro on the Mac, it says on the options screen "No audio track
in source movie", despite the fact that it plays the audio for me.
And if I do the conversion anyway, the resulting file has no audio.

The same thing happens if I try to convert to MPEG-4, or if I do the
conversion within iTunes.

I've also tried converting to H.264 or MPEG-4 using ffmpeg on a linux
machine, following various methods found on the web.  The resulting
files had working audio, but iTunes refused to sync them to the iPod.

Any suggestions for how to handle this?  If there is a more appropriate
forum, please let me know.

Thanks,

Dan