[vorbis-dev] State of Vorbis, 20000409

[Monty]

>      You guys going to be at Streaming Media East in June?  That might be
> a fun time to launch it.

We'll be there; a release/launch will be ready long before then, but we may
want to set this as the 'break out the champagne, the bitstream format is
officially frozen and out of beta' party date.

> http://www.xiph.org/archives/vorbis-dev/0010.html
>    Is this high-level description of the encoding process still accurate?

Yes, although 1.0 wont have the time domain preclamping/preencoding.

>    I'm still interested in what references you have for the
> psychoacoustics, and how you're using them.  The source (I'm guessing
> psy.c is where the action is) isn't particularly heavily commented (though
> it is short).

psy.c is the right file, but the one on the mainline is a very simplistic
algorithm.  The psy.c on the new_acoustics_pending_merge_20000328 branch is the
more sophisticated production algorithm I'm integrating now.

References for the psychoacoustics:

_Masking Patterns of Tones_, Robert H. Ehmer, J. ASA vol 31, no. 8, August 
1959, pp 1115-1120

_Additivity of Different Types of Masking_, Robert C. Bilger, J. ASA vol 31, 
no. 8, August 1959, pp 1107-1109

_Parametric Bit Allocation in a Perceptual Audio Coder_, Grant A. Davidson, 
Louis D. Fielder and Brian D. Link, presented at the 97th Convention of the 
Audio Engineering Society, November 1994

_Masking by Tones vs. Noise Bands_, Robert H. Ehmer, J. ASA vol 31, no. 9 
September 1959. pp 1253-1256

_Evaluation of the Audible Digital Distortion and Noise Produced by Digital 
Audio Converters_, Louis D. Fielder, J. ASA vol 35 no. 7/8, 1987 July/August, 
pp 517-535

(Note that these are papers I used for raw data; the algorithm I use to
determine masking is not taken from any of them.)

Monty

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