I had always assumed (based on nothing but pure ignorance) that audio compression was like text compression -- the less variety, the more compression.

Audio compression can be that way, depending on the implementation of the compression algorithm. MP3 at a constant bit rate isn't like that, however.

And with audio, what counts as "variety" isn't the same as you'd find in a text file. With audio, it tends to be high frequency information that's hardest to compress.

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Tony Fabris