On Thu, 2010-02-04 at 16:22 +0100, Klistvud wrote: > Dne, 04. 02. 2010 14:57:37 je Adam Hardy napisal(a): > > > > How does normalize-audio know that one cd is the sound of pins > > dropping but the next cd is elephants charging? I mean, I don't want > > those cds to be literally the same volume, I want them to keep their > > relative volume difference, but just to adjust the absolute level to > > a standard. > > > > Or is that some Holy Grail that you can't do? > > Common sense tells me that any software that wants to normalize audio > levels, must probably scan the entire sound clip, find the loudest > passage within the clip, and set that passage to the reference 0 db > loudness. All the other passages in the clip just get set to an > accordingly lower level, and that's that. The same goes for entire CDs: > you find the loudest signal in the entire CD, and then proceed > accordingly.
FWIW, the replaygain algorithm uses a more advanced psycho-acoustic model to determine loudness than just "maximum amplitude". I know you are talking about .wav and .flac, but I've used: mp3gain vorbisgain for normalizing the respective audio files. Both of those packages use the replaygain algorithm. -- Matt Zagrabelny - mzagr...@d.umn.edu - (218) 726 8844 University of Minnesota Duluth Information Technology Systems & Services PGP key 4096R/42A00942 2009-12-16 Fingerprint: 5814 2CCE 2383 2991 83FF C899 07E2 BFA8 42A0 0942 He is not a fool who gives up what he cannot keep to gain what he cannot lose. -Jim Elliot
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