[Vorbis] Simple OGG editing without re-encoding?

[Daniel Schregenberger]

On Fre, 2005-01-14 at 14:05 +0100, Marcin Kasperski wrote:
[...]
> a) removing left channel (which is empty) and changing right 
> channel to the mono channel (mono sound stereo-recorded by 
> mistake)
> 
> b) volume change
[...]
> 1) Is it possible to perform those changes 'in place' - without 
> decoding and reencoding? From my naive point of view it seems 
> that those changes should not require reencoding but heavy 
> googling did not help to find any suggestion how to do this.

I don't know about the channel thing, I think it depends on the encoding
quality setting ie. if it's Joint Stereo or real Stereo.
For the volume there's the vorbisgain "standard":
http://sjeng.org/vorbisgain.html

(there are several other pages, I just googled)

> 2) Is re-encoding to be worried about? In other words: if
>     B.ogg = ogg-encode( ogg-decode( A.ogg) )
> is the quality of B.ogg worse than the quality of A.ogg?

Yes. Ogg is lossy. Like mp3, jpeg, mpeg, xvid, ...

-- Daniel


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