[vorbis] APPLAUD.WAV problems

Nicola Larosa nico at tekNico.net
Wed Feb 13 03:44:44 PST 2002



Your description is correct on all fronts. Silly me. :^(

<p> > 1. At -q 0 there are very noticeable CHIRPS ("high-frequency distortions
 > added to the audio, will sound like short chirps, whistles, sometimes can
 > shwoosh up like a high-pitched glissando (slide).")-----BUT I consider
 > this to be normal at such low bitrates.

Now that I know what to listen for, I notice it. And it's not at all subtle. 
Cannot explain why I didn't notice before. :^(

<p> > 2. From approx. -q 1 on the CHIRPS seem to fade out, but there is a *VERY*
 > noticeable BOOSTING OF THE HIGH FREQUENCIES (or high frequency noise) -
 > like if you boosted TREBLE with an equalizer. High frequency boosting has
 > already been discussed on this forum

Yes, high frequency noise. It is definitely there, up to "-q 4.99", even if
you have to strain a bit to hear it at that level.

<p> > The effect becomes less pronounciated as you move towards - q 4.9, but
 > still EASILY audible (16/16 ABX). At -q 5 it suddenly fades out (I've
 > heard that something changes in the encoding method at that point), but
 > also the bitrate jumps substantially.

Yes, it disappears completely at "-q 5": that's where the lossless stereo
encoding kicks in. It looks like the lossy stereo encoding cannot encode the 
big differences between the two channels in this sample.

<p> > LAME does a **MUCH** better job, even at 128 kbps (!!). This really
 > confuses me, because I use OGG and consider it to be a better performer
 > otherwise.

Maybe the lossy stereo encoding will be tuned a little bit more before 1.0.

<p> > I'm sure that many others have noticed this problem. Is it possible,
 > Nicola, that your speakers fade out high frequencies?

No, it definitely looks like a problem concerning the grey matter between
the ears. :^(

<p>
-- 
"MP3 the king is a mighty warrior, but he's showing new wounds.
Ogg [Vorbis] is the successor to the throne ... In this case,
Open Source is not a compromise; Vorbis is the best out there."
-- Monty (Mr. Vorbis) on Slashdot

Nicola Larosa - nico at tekNico.net

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