Re: VQ vector value decode help
"N. Sidorova" <[email protected]> Mon, 22 Apr 2013 16:38:27 -0600
| Newsgroups | gmane.comp.multimedia.ogg.vorbis.devel |
|---|---|
| Message-ID | <[email protected]> |
On 4/22/2013 10:22 AM, [email protected] wrote: > On Sun, Apr 21, 2013 at 11:24 AM, N. Sidorova <[email protected]> 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.