Earlier quoted context omitted.
re-encoding an mp3 doesn't do much Sure it does, typically. It’s no different from video in this way: ideally, all of the image features that would get thrown out were thrown out the first time, but the codec isn’t that smart. Most implementations of lossy compression algorithms don’t have stability under re-encoding as a goal. (A few do – some image editors are smart about passing through unchanged JPEG blocks, for…
Why hypothesize? Create a directory. Copy your favorite MP3 into it as both "source.mp3" and "orig.mp3". (orig.mp3 is just for convenient comparison later.) Then: for i in {1..100}; do lame source.mp3 dest.mp3; mv -f dest.mp3 source.mp3; done Then listen to the resulting "source.mp3" at the end. Send whatever params to lame you want in that command line, though the defaults strike me as pretty good for this test. BTW…
Learning how to do for loops in shell was a big Unix productivity breakthrough for me. I just wish the syntax were cleaner – silly things like quoting rules and not using $ on variables on the LHS keep tripping me up. I’m probably wasting my own time in the long run by not getting good with something like http://www.scsh.net/ .