Another approach would be to do all your audio stuff in an easier format (WAV for example) and have your perl script encode it as mp3 as the final step.

When I bring music into my collection I convert all input files to WAV, do all my adjustments (volume normalisation etc) using the WAV format files and then call "lame" at the end to create an mp3 that works everywhere (well really the final step is tagging my created mp3, but you get the idea).