[vorbis] Amplify Ogg files without decode/encode

[Mike Coleman]

Ross Levis <ross at soulfm.cjb.net> writes:
> Just curious, is it possible to amplify Ogg frames without a decode/encode
> cycle?  I usually normalise before encoding all recordings for my radio
> station, but I obtain some music from 3rd parties and it often need
> normalising.  I find this ability very useful for MP3s and it would be a big
> handicap to me if Ogg can not.

I was thinking before that it was possible to adjust the absolute "volume" of
each analysis packet via some simple tweak, but after looking at the source
for a bit (circa January source), I don't see any way this can currently be
done.

It would be possible, I think, to change the stream format to add some sort of
"volume escape" packet or something, but it's not currently there.  This is
very annoying, actually, as the ability to easily munge a vorbis file to add
fade-in/fade-out would be very nice.  Along the same lines, for editing
purposes, it would be nice to have some sort of escape that would tell the
player (or whatever) to ignore the first (or last) n PCM samples in a stream.

One (not especially pretty) way to add these features would be to specify some
"meta markers" that could be added at the ogg stream level, without changing
the vorbis stream, that a player could use to control playback.

--Mike


-- 
Mike Coleman, mkc at mathdogs.com
  http://www.mathdogs.com -- problem solving, expert software development

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