[vorbis] questions about artifacts in low bitrate streams

[Michael Smith]

>- Is this a known issue with the beta in low bitrate encoding?
>
>-If a known issue, is it on target to be fixed in a future beta or the 1.0
>final release?

There are two issues here:

Firstly, low-bitrate encoding is definately NOT well tuned currently. You
shouldn't expect it to work really well right now - version 1.0 will
certainly perform better on low bitrates. However, this is almost certainly
not the problem you're encountering.

The other problem was a bug in pre-beta4 decoders. They didn't implement a
feature which is used by the beta4 encoder at low bitrates, and incorrectly
didn't note this fact (so they tried to play back files that they don't
know how to). The symptoms are pretty much exactly what you described. I'm
not sure if sonique has updated the version of vorbis they use to beta4 yet
- last time I looked they hadn't. As a result, lower bitrate files will be
decoded incorrectly. I suspect that the same is true of the mac player you
said you tried. 

Could you use either freeamp (2.1, which was released a couple of days ago
with built-in vorbis support), or winamp with the beta4 plugin from
www.vorbis.com to test this, to check that this is indeed the problem it
appears to be?

Michael

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