[vorbis] APPLAUD.WAV problems

[Bostjan]

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----- Original Message -----
From: "Monty" <xiphmont at xiph.org>
To: <vorbis at xiph.org>
Sent: Saturday, February 16, 2002 9:53 PM
Subject: Re: [vorbis] APPLAUD.WAV problems

At mid-to-low bitrate, it's not fair to blame *any* encoder.  Some do
better than others, but if audiophile quality is your concern, -q4 in
Ogg or 128 in LAME is just to low to take seriously (I think we both
agree here).
>>>>>>>>

Yes. I nevertheless really admire the near-transparency quality that OGG
attains at 4x-6x lower bitrate than lossless encoders (with "normal" music).

<<<<<<<<<
However... that's not to say that there's a loooong road of possible
stereo analysis improvements possible in the future, nor am I saying
that there's no room for improvement in applaud.wav that won't also
benefit other samples.
>>>>>>>>>

I agree: if the noise effect is so evident in APPLAUD.WAV, it is almost
certainly present in other samples also (though barely audible). The
question now is how to make OGG aware of when does it become audible.

<<<<<<<<<
Yes, lossless coupling is a big help to this sample.  The encoder does
not have any analysis code currently to look at noise resolution
taking into account an out-of-phase stereo field.  Right now it
believes that moving that noise energy to the center is acceptible
(which it obviously isn't), and it's performing correctly as per the
current algorithm.  Analysis needs to be strengthened to take this
into account.
>>>>>>>>

Thank you for your understanding. The applaud issue was the only one that
made me think about OGG's performance. OGG is otherwise outstanding! No
other encoder has such huge bitrate range setting (approx 64 - 500
kbps), real VBR, open source and so consistent quality.

<<<<<<
LAME maintains the stereo image because it isn't capable of
automatically moving noise localization around to save bits.  It
maintains the stereo field by accident ;-)
>>>>>>

Hm, that's another good news :)
Regards,
Bostjan

<p>--- >8 ----
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