Re: VQ vector value decode help
[email protected] Mon, 22 Apr 2013 12:22:16 -0400
| Newsgroups | gmane.comp.multimedia.ogg.vorbis.devel |
|---|---|
| Message-ID | <CACrD=+_vBZgyPuOSGk-r4ujceAf-zOwxR=Mtsskm_i1igB7sSA@mail.gmail.com> |
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