[Vorbis-dev] VQ vector value decode help

[N. Sidorova]

On 4/22/2013 10:22 AM, xiphmont at xiph.org wrote:
> On Sun, Apr 21, 2013 at 11:24 AM, N. Sidorova <n.sidorova at lunanite.com> wrote:
>> Hello,
>>
>> I've been writing a decoder using the spec and it's unclear to me where
>> the value [lookup_offset] comes from when performing VQ vector value
>> decode (page 23 of the spec). The wording in the spec is very confusing
>> to me. Someone asked this question before (
>> http://lists.xiph.org/pipermail/vorbis-dev/2002-September/015282.html ),
>> but it went unanswered.
>>
>> Could anyone help me (and anyone in the future) understand where this
>> value is coming from?
> I assume you're talking about section 3.2.1.
>
> A codebook conceptually consists of a list of vectors; the
> input_offset is the number of a given vector in the list.
>
> The pseudocode is showing the decoding process for a single one of
> those vectors; there's an implied higher level loop that is decoding
> each vector in turn.
>
> Monty
Thanks! I believe you're saying that the implied loop is for each entry 
in the [codebook_multiplicands] array, with [lookup_offset] being the 
index of the [codebook_multiplicand] array entry for a given iteration. 
Is this understanding correct?

Also, when I've finished implementing the spec I'd like to submit a list 
of the typos I've found. Is this something best done on Trac or on this 
mailing list?

Cheers.