[vorbis-dev] Re: [vorbis] Amplify Ogg files without decode/encode

[Monty]

> you'll need to
> be very careful that every block gets scaled up (or down) by very
> exactly the same
> value, as otherwise you will certainly hear it, esp. in the bass
> frequencies (it'll
> generate artificial overtones, somewhat like the well-known mp3 blips).

Add/subtract the same amount to every block.

> If, on the other hand, you scale the residue values, you'll only need to
> do it in the
> codebook headers, and you don't need to worry too much about precision,
> as every block
> will get scaled by the exact same factor.

Segher is correct here, and stopping to think about it, he has a good
point.  You can scale the residues by adjusting two values in each
residue codebook.

Monty

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