[vorbis] That pesky udial.wav again...

[John Morton]

On Tuesday 15 January 2002 15:03, Gian-Carlo Pascutto wrote:
> On Tue, 15 Jan 2002, John Morton wrote:
> > Now I _know_ that high frequency sine wave sweeps are a completely
> > contrived sample to test an audio codec with, but I'd hate to think that
> > some idiot kid on slashdot will end up badmouthing vorbis because it goes
> > to pieces on a sample like this. It would be a lot nicer if it failed to
> > include the sweep and didn't contain artifacts.
>
> Vorbis is doing you a favor. If you play udial on a stereo system with
> tweeters and have the volume a bit too loud, it will blow them out.
> Really.

I'm aware of that, however I suspect the artifacts might do the same at high 
volumes as well. I'd prefer it if vorbis did neither, by default - perhaps 
doing a polyphase lowpass filter right out to quality 10.0 unless you switch 
the filter off (like -k does in lame).

> Anyone using that clip to test a codec will auto-LART themselves sooner or
> later.

:-) I alway do this sort of testing with a pair of cans for just that sort of 
reason.

> Now, it's been a while since I saw it, but I seem to remember it did clip.
> If it does, there's no guarantee it'll play back fine, even if the encoder
> handles it ok. But that's why Vorbis now has...(see next post :)

It might do. Maybe I should put the sample up somewhere with a selection of 
the encodes, so you can compare behaviour between vorbis and lame.

John

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