Matthew T. Russotto wrote:
In article <1168868350.414093.269480@a75g2000cwd.googlegroups.com>, <bieling@terra.es> wrote:Let's say that we've got a music file with a bitrate x. We burn this file into a CD (AIFF), then we encode it from the CD's AIFF into another mp3 file with the same bitrate x as the original. The question is, have we really lost any quality in the process? I ask because I'm not so sure... ?If you use exactly the same codec with exactly the same settings, I'd hope there would be no quality loss. I don't know if this is the right term, but I call this a "stable" codec -- one where C(D(x)) = x
That's the property I was referring to as "information-preserving". I suppose "idempotent under repeated codec cycles" also gets it. This is such an important property that I'm surprised that it isn't noted (yes or no) on virtually every compression algorithm. The 2:1 ADPCM compression I implemented for sounds in SOUND.EDITOR (and whose codec source is on my web site) has that property. -michael NadaNet networking for Apple II computers! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."