Before the current Xing engine, there was a thing (awfull) called tompg.exe
from xing for mpeg audio encoding. I can send it to you if you're
interested, but it's a win32 file.
The interesting thing is that there is an option in it to specify to pass or
not in the psy model, or to let the encoder choose.
The other thing I'm quite sure is that they don't choose what huffmann table
to use, they only use a fixed one.
Gabriel Bouvigne - France
[EMAIL PROTECTED]
icq: 12138873
MP3' Tech: www.mp3tech.org
----- Message d'origine -----
De : Mark Taylor <[EMAIL PROTECTED]>
� : <[EMAIL PROTECTED]>
Envoy� : lundi 7 juin 1999 00:07
Objet : Re: [MP3 ENCODER] VBR suggestions
>
> >
> > Xing speed is still a mystery. It's obvious that mmx asm is not the only
key
> > of their speed...
> >
>
> I took a look at some of Mike's Xing/VBR castanets.wav encodings. One
> interesting thing: Xing never uses short blocks! So I will go ahead
> and guess that they still do not bother with psycho-acoustics. The
> probably use reasable, but fixed, masking thresholds (we should add
> this to LAME -f) This could explain their speed and pre-echo problems
> at 128kbs. If you dont compute the psycho acoustics, you cant tell if
> you should do some window switching.
>
>
> >
> > I made a mistake here (I forget the 2 granules for each channel)
> > so replace it by:
> >
> > if (4over<over_limit)
> > bitrate--;
> >
>
> okay, now I understand. I will add this to LAME. And it is clear
> Xing/VBR is doing some very aggressive bitrate reductions. I've seen
> them encode some frames as low as 64kbs, while the previous frame was
> 256kbs.
>
> Mark
>
>
>
>
>
>
> --
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>
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