[Ffmpeg-cvslog] CVS: ffmpeg/libavcodec dsputil.c, 1.123, 1.124 dsputil.h, 1.117, 1.118 h264.c, 1.136, 1.137

Måns Rullgård mru
Fri Jun 17 13:08:51 CEST 2005

Loren Merritt <lorenm at u.washington.edu> writes:

> On Fri, 17 Jun 2005, [iso-8859-1] M?ns Rullg?rd wrote:
>> Loren Merritt <lorenm at u.washington.edu> writes:
>>> I won't have time for more lavc development for a while, so if you
>>> want to start on custom quant matrices, it won't be a duplication of
>>> effort.
>> OK.  Have I understood correctly that the dequant[48]_coeff arrays
>> should be moved to the SPS/PPS, and calculated from the scaling lists?
>> The custom matrixes are different for intra/inter blocks and
>> luma/chroma.  Do you have any ideas/opinions on how to best represent
>> that?
> There should be 8 pointers in each SPS and PPS, which may be populated
> from the stream or from the default matrices (with a bunch of
> inheritance rules). Decoding always uses the pointers from the current
> PPS; the SPS ones are just there in case you have multiple PPSs
> referencing the same SPS.

What's in the current dequant[48]_coeff?  It looks like precomputed
scaling values for all QP with the default scaling matrix (all 16).

> luma and chroma are already decoded in different places, just hardcode
> which CQM pointer you need at each one. For intra/inter and U/V, it
> just takes one more index into the list of CQM pointers.

So basically it's just a matter of replacing h->dequant4_coeff with

>> Does anyone have a sample with a custom quant matrix in the PPS?
> maybe at http://ftp3.itu.ch/av-arch/jvt-site/draft_conformance/FRExt/
> (But I can't tell you which one; I haven't examined all the streams)

Well, a bunch of files is a good start.

M?ns Rullg?rd
mru at inprovide.com

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