[vorbis-dev] Re: [vorbis] Ogg Vorbis in Audiograbber and more

[Rajko.Jersic]

Hi!
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> Putting patent issues aside, lame's joint-stereo is rather rudimentary
> (this actually isn't lame's fault - that's the way mp3 was designed)
> because joint-stereo switching is estimated for a complete block -
> so either the whole block is suitable for m/s coding, or it isn't -
> some other newer formats like AAC have more sophisticated
> joint-stereo because they can encode part of the spectrum using
> m/s while leaving the rest in stereo - it's more efficient but also
> a bit more complicated to implement.
>
> But I don't know what kind of joint-stereo will be used in Vorbis.

Maybe Monty knows?
What will it be?
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>could you please sum up the major quality improvements that have
>already been planned but are stil to be implemented im vorbis?

I'd like to know too.
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I tried beta 4. I tested it, the way I always test a new codec.
I use some kind of looking at and listening to the difference of original
and decoded signal, and sometimes the difference between 2 decoded signals
from different bitrates.

Of course I compare everithing to lame. And I don't care what you think of,
but I use "-h -b 320 -mj -d" for my encoding.
(looking at the difference Vorbis is nearly as good as lame, but listening
to the difference - lame is still better)

What I found out?

I think the problem is in masking.

Masking of some frequences should be tuned some more.
The freqencies I suspect are: 130 Hz, 300-330 Hz, 500 Hz, 850 Hz, 1200 Hz,
1600Hz, 1875 Hz, 9000 Hz,
At lover bitrates some amplitudes get too amplified. That makes a lot of
clipping.
I don't really know, but I think masking and clipping are somehow conected
problems.
Tune masking and maybe there will be less clipping.
Even at 350kbps there is heavy masking out of high frequencies.

Anyway I think Vorbis is nearly as good as lame. Has a lot of potential,
while lame has developed as far as it could come in mp3 format.
Maybe the next beta (beta 5) or Vorbis 1.0 will be much much better. If the
quality improvement will be as big as from beta 3 to beta 4?
Oh, When do you plan for the next release?

I hope you guys don't resent me. I'd just like to help.

__________________
rajko.jersic at siol.net
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