[FFmpeg-devel] [PATCHSET] AAC decoder refactor

[Lynne]

Apr 22, 2024, 09:20 by dev at lynne.ee:

> Apr 22, 2024, 00:19 by michael at niedermayer.cc:
>
>> On Fri, Apr 12, 2024 at 11:11:53AM +0200, Lynne wrote:
>>
>>> Apr 12, 2024, 00:45 by michael at niedermayer.cc:
>>>
>>> > On Thu, Apr 11, 2024 at 07:42:37AM +0200, Lynne wrote:
>>> >
>>> >> Apr 10, 2024, 23:57 by michael at niedermayer.cc:
>>> >>
>>> >> > On Wed, Apr 10, 2024 at 08:18:11PM +0200, Michael Niedermayer wrote:
>>> >> >
>>> >> >> On Wed, Apr 10, 2024 at 06:48:26PM +0200, Lynne wrote:
>>> >> >> > Apr 8, 2024, 09:36 by dev at lynne.ee:
>>> >> >> > 
>>> >> >> > > The following patchset refactors the AAC decoder step by step,
>>> >> >> > > removing all large-scale templating and abstracting away typed
>>> >> >> > > DSP functions from symbol parsing.
>>> >> >> > >
>>> >> >> > > This series saves 110Kib of binary data from libavcodec.so
>>> >> >> > > when compiled with Clang 18 with -O3, after stripping.
>>> >> >> > >
>>> >> >> > > The patchset can also be viewed here:
>>> >> >> > > https://github.com/cyanreg/FFmpeg/tree/aac_cleanup
>>> >> >> > >
>>> >> >> > > Fate passes on each step, and I've been running this patchset for
>>> >> >> > > a week with no issues.
>>> >> >> > >
>>> >> >> > > This also prepares the decoder for USAC support.
>>> >> >> > >
>>> >> >> > 
>>> >> >> > I've rebased the linked repo to current git master if anyone
>>> >> >> > wants to test.
>>> >> >>
>>> >> >> thanks, i will try to test it
>>> >> >>
>>> >> >
>>> >> > make fate-source
>>> >> >
>>> >> > TEST    source
>>> >> > --- ./tests/ref/fate/source	2024-04-08 18:26:00.670129617 +0200
>>> >> > +++ tests/data/fate/source	2024-04-10 23:56:18.032896853 +0200
>>> >> > @@ -22,6 +22,13 @@
>>> >> >  compat/djgpp/math.h
>>> >> >  compat/float/float.h
>>> >> >  compat/float/limits.h
>>> >> > +libavcodec/aac/aacdec.h
>>> >> > +libavcodec/aac/aacdec_fixed_coupling.h
>>> >> > +libavcodec/aac/aacdec_fixed_dequant.h
>>> >> > +libavcodec/aac/aacdec_fixed_prediction.h
>>> >> > +libavcodec/aac/aacdec_float_coupling.h
>>> >> > +libavcodec/aac/aacdec_float_prediction.h
>>> >> > +libavcodec/aac/aacdec_latm.h
>>> >> >  libavcodec/bitstream_template.h
>>> >> >  tools/decode_simple.h
>>> >> >  Use of av_clip() where av_clip_uintp2() could be used:
>>> >> > Test source failed. Look at tests/data/fate/source.err for details.
>>> >> > tests/Makefile:310: recipe for target 'fate-source' failed
>>> >> > make: *** [fate-source] Error 1
>>> >> >
>>> >>
>>> >> Thanks for testing. Fixed both issues in the repo.
>>> >> Was only testing with fate-aac while developing.
>>> >>
>>> >
>>> > mips:
>>> >
>>> > make  -k
>>> > LD	ffmpeg_g
>>> > libavcodec/libavcodec.a(aacsbr.o): In function `ff_aac_sbr_ctx_alloc_init':
>>> > aacsbr.c:(.text.unlikely+0x1d4): undefined reference to `ff_aacsbr_func_ptr_init_mips'
>>> > aacsbr.c:(.text.unlikely+0x200): undefined reference to `ff_aacsbr_func_ptr_init_mips'
>>> > libavcodec/libavcodec.a(sbrdsp.o): In function `ff_sbrdsp_init':
>>> > sbrdsp.c:(.text.unlikely+0x10): undefined reference to `ff_sbrdsp_init_mips'
>>> > sbrdsp.c:(.text.unlikely+0xb4): undefined reference to `ff_sbrdsp_init_mips'
>>> > libavcodec/libavcodec.a(aacpsdsp_float.o): In function `ff_psdsp_init':
>>> > aacpsdsp_float.c:(.text.unlikely+0x10): undefined reference to `ff_psdsp_init_mips'
>>> > aacpsdsp_float.c:(.text.unlikely+0x6c): undefined reference to `ff_psdsp_init_mips'
>>> > collect2: error: ld returned 1 exit status
>>> > Makefile:136: recipe for target 'ffmpeg_g' failed
>>> > make: *** [ffmpeg_g] Error 1
>>> > LD	ffprobe_g
>>> > libavcodec/libavcodec.a(aacsbr.o): In function `ff_aac_sbr_ctx_alloc_init':
>>> > aacsbr.c:(.text.unlikely+0x1d4): undefined reference to `ff_aacsbr_func_ptr_init_mips'
>>> > aacsbr.c:(.text.unlikely+0x200): undefined reference to `ff_aacsbr_func_ptr_init_mips'
>>> > libavcodec/libavcodec.a(sbrdsp.o): In function `ff_sbrdsp_init':
>>> > sbrdsp.c:(.text.unlikely+0x10): undefined reference to `ff_sbrdsp_init_mips'
>>> > sbrdsp.c:(.text.unlikely+0xb4): undefined reference to `ff_sbrdsp_init_mips'
>>> > libavcodec/libavcodec.a(aacpsdsp_float.o): In function `ff_psdsp_init':
>>> > aacpsdsp_float.c:(.text.unlikely+0x10): undefined reference to `ff_psdsp_init_mips'
>>> > aacpsdsp_float.c:(.text.unlikely+0x6c): undefined reference to `ff_psdsp_init_mips'
>>> > collect2: error: ld returned 1 exit status
>>> > Makefile:136: recipe for target 'ffprobe_g' failed
>>> > make: *** [ffprobe_g] Error 1
>>> > make: Target 'all' not remade because of errors.
>>> >
>>>
>>> Fixed. This should be all.
>>> On the Loongson machine I have access to, I can't compile FFmpeg
>>> due to missing asm/errno.h kernel header, while on the standard MIPS64
>>> machine I can access, compilation worked either way.
>>>
>>> Would you mind testing again the new version in the repo?
>>>
>>
>> it works on my qemu based mips. I did give the loongson to anton 2 years ago
>> so i have no native loongson to test it with
>>
>
> Thanks. That sounds good enough for me, really the main
> potential issue I see with this is that it changes the way files
> are organized to be more like the VVC decoder.
> Since no one seems bothered by that, I'll move on with pushing
> this tomorrow.
>

Patchset pushed. Thanks for the reviews and testing,
and for Andreas for the commits he did.

Final savings:
All measurements done on libavcodec/libavcodec.so.61 with a
default configuration after stripping:

x86-64:

clang-18 with -Os
Before: 10601800
After:  10589512

clang-18 with -O3
Before: 15377624
After:  15340760

gcc-14 with -O3
Before: 15377624
After:  15340760

gcc-14 with -Os
Before: 10601800
After:  10589512

aarch64:

gcc-12 with -O3
Before: 12444560
After:  12399504

clang-17 with -O3
Before: 12436368
After:  12399504

Disabling everything but audio encoders and decoders
seems like it saves more, but to keep it far, this is the
default config with everything enabled.