[vorbis] RC3?

[Beni Cherniavksy]

On 2002-01-02, Monty wrote:

> > really now. And you forgot to mention the several dozen "I want a
> > MP3-to-OGG converter" debates that rage through that forum. Yawn.
>
> Oh, true enough.  Probably the most annoying group of posts.  OTOH,
> these folks can't *really* be faulted as much; many understand that
> the quality will be suboptimal, but they want very much to switch
> anyway as a symbolic gesture.  The motivation is commendable even if
> the practicalities aren't.
>
> Monty
>
Is there a good and simple way to have the encoder guess that the spectrum
it's being fed is allready a result of some perceptive compression, e.g.
MP3?  For example seeing that very little masking happens?

Then, if detected at large enough portion of the frames, the encoder lib
will e.g. call a callback provided by oggenc (NULL to disable checking and
gain speed) that will print a big shouting warning ~ "This input seems
like an output of previous lossy compression (e.g. mp3).  IF YOU ARE
REALLY TRANSCODING FROM MP3 (or any other lossy codec), THE QUALITY WILL
BE EVEN WORSE THAN THE MP3.  WE WARNED YOU...!!!  (set `OGGENC_NOCHECK'
environment variable to disable these warnings and gain a little speed)."

Similarly with other encoder interfaces, especially the easiest GUIs
(oggdrop).


-- 
Beni Cherniavsky <cben at tx.technion.ac.il>
                 (also scben at t2 in Technion)
Happy new 2 (mod 100).

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