> Please note that the subject of this conversation is mp4 (not mp3). It's claimed that sox will handle mp4: https://stackoverflow.com/questions/2666425/how-to-i-configure-sox-to-work-on-mp4 (You do have to install LAME.) > If you only process uncompressed audio then sox is fine. It will do the mp's and flac. That I know of -- there may be others. It normalizes things too. I do that in flac. I don't know if it normalizes mp's. -- Glenn English