[MPlayer-users] Re: 3-pass encodes with ogg vorbis?

* afe0108 at yahoo.com
Wed Jan 21 18:49:26 CET 2004

--- Tobias Diedrich <ranma at gmx.at> wrote:
> D Richard Felker III wrote:
> > On Mon, Jan 19, 2004 at 06:09:20PM +0000, Goran Hane wrote:
> > > Just a thought, but why don't use normalize for audio-normalization, just
> > > run normalize audiodump.wav after the audio is extracted and then oggenc
> > > it?
> > 
> > NEVER blindly normalize audio. It will hurt quality severely if your
> > samples frequently go near +-32767, since frequency-space codecs
> > cannot reliably reproduce these values without clipping. If your
> normalize does not maximise the audio volume, but rather adjusts the RMS
> volume to a defined level. In most cases normalize decreases the volume.
> And I use it exactly because of that when I grab a CD[1] and make mp3s/oggs
> from it, so that it does not clip on decoding.
> -- 
> Tobias						PGP: http://9ac7e0bc.2ya.com
> This mail is made of 100% recycled bits.
Sorry, does RMS mean it will never raise the volume enough to cause
clipping?  Or perhaps that depends on the target amplitude, which
seems to default to 0.25?

For the src of transcode's tcscan, it looks like it's normalizing
using the peak amplitudes which I think would result in the clipping
Rich mentioned.  So I will definitely cease and desist with that.


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