Vorbis dev - Aug 2001 - extremely noticeable artifact (britney-bug)

I really don't know if this is the same problem that was reported by Ingo
Saitz (I really couldn't say which one was 128kbit and which was the
original wav when blind-testing. The original had some distortion that
perhaps does somehting with my cheapo soundcard) but here's a description
of what i've found:

When doing some sample encoding with rc2 (rebuilt rpm with latest redhat
7.1 gcc errata) I got some extremely loud treble distortion sounds in the
left channel (only). Please listen to the samples at low level to avoid
hurting your ears. My guess is that the bug is related to the channel
coupling mode used in 128bit and 80bit mode because that's the only modes
that exposes this behaviour.

A 6 second sample of the problem is available from
http://noa.tm/britney-bug/

By the way, the documentation on http://www.vorbis.com/stereo.psp indicates
that there is a way to select stereo mode with oggenc, but that don't seem
to be documented.

cheers
/daniel

ps. apart from this problem, the rc2 release sounds great. All of the
annoying artifacts i've found with beta4 128kbit seems to be magically
gone. Great work!


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----- Original Message -----
From: "Daniel Resare" <noa@metamatrix.se>
To: <vorbis-dev@xiph.org>
Sent: Monday, August 20, 2001 9:22 AM
Subject: [vorbis-dev] extremely noticeable artifact (britney-bug)
> By the way, the documentation on http://www.vorbis.com/stereo.psp
indicates
> that there is a way to select stereo mode with oggenc, but that don't
seem
> to be documented.
This is a misunderstanding. You can select the stereo mode via the
encoding mode/bitrate. You can't select it seperately -yet-.


--
GCP

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----- Original Message ----- 
From: "Daniel Resare" <noa@metamatrix.se>
To: <vorbis-dev@xiph.org>
Sent: Monday, August 20, 2001 9:22 AM
Subject: [vorbis-dev] extremely noticeable artifact (britney-bug)
> When doing some sample encoding with rc2 (rebuilt rpm with latest redhat
> 7.1 gcc errata) I got some extremely loud treble distortion sounds in the
> left channel (only). Please listen to the samples at low level to avoid
> hurting your ears. My guess is that the bug is related to the channel
> coupling mode used in 128bit and 80bit mode because that's the only
modes
> that exposes this behaviour.
> 
> A 6 second sample of the problem is available from
> http://noa.tm/britney-bug/
That page is giving me 404 Not Found errors :(

PS. I found a sample yesterday that could not even be decoded in 128 and 
160kbps modes!


-- 
GCP

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> october: release 2.0rc1, rc2, rc3pre1, rc3pre2ac1
When Alan Cox is making vorbis-patches we know we have come 
far... :-D

// Wigren

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