[vorbis-dev] Test files for decoder implementation

Monty xiphmont at xiph.org
Fri Sep 20 02:59:50 PDT 2002

> >Please, inform us of any 'obvious mistakes'.
> Most turned out to be my mistakes (typos and such), but one left 
> is when decoding the mappings from the setup header:
> vector [vorbis_mapping_magnitude] element [j]= read ilog([audio_channels]) 
> bits as unsigned integer
> vector [vorbis_mapping_angle] element [j]= read ilog([audio_channels]) 
> bits as unsigned integer
> Both steps should read:
> .. read ilog([audio_channels] - 1) bits ...

I have verified that you are correct, and updated the spec in CVS and

> The libvorbis implementation also differs from the format documentation 
> in variable naming and algorithm implementation. Different variable 
> naming is of course not really an error, and using different algorithms 
> and storage structures not necessarily (probably rather an optimization 
> of the decoding process), but it would be much easier to understand 
> the format specification if they would match each other. At least 
> it makes it impossible to compare a partial result from my implementation 
> with whatever libvorbis has computed up to this point of the decoding 
> process. Specific examples for this could be the last part of the 
> residue header decoding process where libvorbis uses a 1-dimensional 
> array with only the used codebooks, and the format specification 
> uses a 2-dimensional array, marking unused entries as such, hence 
> the residue packet decoding process is also very different.

The intent was to simplify the explanation such that it was easier to
understand, even if this would produce code that was literally less

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