mp3asm

mp3asm is a software for editing mpeg 1/2/2.5 audio layer 1/2/3 (cbr/vbr) frame levels that adheres to the mpeg audio standard. The current textmode version allows users to cut, copy, and paste frames without violating this standard. While some people may prefer decoding, wav editing, and re-encoding, these methods can have consequences. Encoders use advanced filtering to create audio data that is easy to compress, resulting in hardly any difference (depending on BR). These filtered audio data are then compressed.

Filtering only once from the original full-range unfiltered audio will provide the best result without wasting precious cycles on a lengthy process. Users can edit mp3 files down to just 40ms, without sacrificing much quality. In fact, further filtering will result in more data loss as encoders differ only in their filterbanks.

With mp3asm, users can salvage a rip that may have otherwise gone to waste due to bad starting frames or a long lead out. It may even be possible to provide for fading in/out, although this is still under development.

While it is unclear why the developer, Olli Fromme, halted development back in '97, mp3asm is still an unbelievable idea that was executed well. The latest release fixed parsing sideinfo for mpeg 1 layer 3 mono, found by Alain Daurat.