[vorbis-dev] Argh, preecho mistriggers

[Monty]

In case people on the list don't know it, A Vorbis tester (who's email I've 
lost!  If you're on the list, speak up!) is maintaining a vorbis audio quality 
test page:

http://hem.passagen.se/ingets1/vorbis.htm

He's doing us the great service of hunting down samples that break Vorbis (so
we don't have to :-)

In any case, it turns out that the trumpets in the dr4 sample are reliably mistriggering the preecho detector (which implies either a large bug in the detector, or general borkkenness which must be fixed).  The artifacts in the sample are due entirely to Vorbis trying to encode the trumpets entirely in short blocks (which will suck for strongly periodic/harmonic waveforms, as produced by brass instruments).

Just a heads up; if someone else runs across this artifact (it manifests as
'wayyy to much noise/rasp'), you know that I knwo about it. 

Monty

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