[FFmpeg-devel] [PATCH] aacdec: convert to lavu/tx and support fixed-point 960-sample decoding

Michael Niedermayer michael at niedermayer.cc
Sun Oct 30 21:39:42 EET 2022


On Fri, Oct 28, 2022 at 11:46:58PM +0200, Lynne wrote:
> This patch replaces the transform used in AAC with lavu/tx and removes
> the limitation on only being able to decode 960-sample files
> with the float decoder.
> This commit also removes a whole bunch of unnecessary and slow
> lifting steps the decoder did to compensate for the poor accuracy
> of the old integer transformation code.
> 
> Overall float decoder speedup on Zen 3 for 64kbps: 32%
> 
> Patch attached.
> 
> Note: lavu/tx's PFA 960pt transform currently has a bug that'll get fixed
> by my next patchset. The naive transforms are unaffected and may
> be used to test 960pt fixed-point decoding.

>  configure                           |    4 -
>  libavcodec/aac.h                    |   27 +++++----
>  libavcodec/aac_defines.h            |    4 -
>  libavcodec/aacdec.c                 |    4 -
>  libavcodec/aacdec_fixed.c           |    5 +
>  libavcodec/aacdec_template.c        |  106 +++++++++++++-----------------------
>  libavcodec/aacsbr.c                 |    1 
>  libavcodec/aacsbr_fixed.c           |    1 
>  libavcodec/mips/aacdec_mips.c       |    4 -
>  libavcodec/sinewin_fixed_tablegen.c |    3 +
>  libavcodec/sinewin_fixed_tablegen.h |    6 ++
>  11 files changed, 74 insertions(+), 91 deletions(-)
> 941b6d4662dd9808266b80fbafb5f003a734a415  0001-aacdec-convert-to-lavu-tx-and-support-fixed-point-96.patch
> From 95625b470fb61676e838310dc0108eb648f972a3 Mon Sep 17 00:00:00 2001
> From: Lynne <dev at lynne.ee>
> Date: Fri, 28 Oct 2022 21:36:10 +0200
> Subject: [PATCH] aacdec: convert to lavu/tx and support fixed-point 960-sample
>  decoding
> 
> This patch replaces the transform used in AAC with lavu/tx and removes
> the limitation on only being able to decode 960-sample files
> with the float decoder.
> This commit also removes a whole bunch of unnecessary and slow
> lifting steps the decoder did to compensate for the poor accuracy
> of the old integer transformation code.
> 
> Overall float decoder speedup on Zen 3 for 64kbps: 32%

This needs a update to fate checksums here:
make: *** [fate-filter-meta-4560-rotate0] Error 1
make: *** [fate-prores-gray] Error 1
make: *** [fate-autorotate] Error 1

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many that live deserve death. And some that die deserve life. Can you give
it to them? Then do not be too eager to deal out death in judgement. For
even the very wise cannot see all ends. -- Gandalf
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