Re: [FFmpeg-devel] gcc: Remove auto-vectorization limitation.

[Frank Plowman <post@frankplowman.com>]

On 21/05/2025 11:17, Jiawei wrote:
> 
> 在 2025/5/21 14:52, Nicolas George 写道:
>> Jiawei (HE12025-05-21):
>>> 					  particularly improving
>>> performance on x86_64 (AVX), ARM64 (SVE) and RISC-V(RVV) architectures.
>> Benchmark needed.
>>
>> Regards,
> 
> 
> Hi Nicolas,
> 
> 
> Since I am a gcc developer, I'm not so familiar with the FFmpeg test 
> flow, here is my test process,
> if there exists anything uncorrect, please point me out:
> 
> 
> 1. Download the video bbb_sunflower_2160p_30fps_normal.mp4.zip 
> <https://download.blender.org/demo/movies/BBB/bbb_sunflower_2160p_30fps_normal.mp4.zip> 
> from https://download.blender.org/demo/movies/BBB/，
> 
> ```
> 
> ffmpeg -i bbb_sunflower_2160p_30fps_normal.mp4 -t 60 -vf 
> "scale=1920:1080" -c:v libx265 -c:a libmp3lame 1080p_hevc_mp3.mp4
> ```
> 
> get the 1080p video as Benchmark test video
> 
> 
> 2. Build two version of FFmpeg, one with the modify,  another without 
> the patch modif, using the gcc 13.3 release version,
> 
> verified with Intel(R) Core(TM) Ultra 9 285HX
> 
> 
> Using patch:
> 
> ```
> ./ffmpeg -benchmark -i ~/mp/1080p_hevc_mp3.mp4 -f null -
> ffmpeg version N-119636-g96518c8d8d Copyright (c) 2000-2025 the FFmpeg 
> developers
>    built with gcc 13 (Ubuntu 13.3.0-6ubuntu2~24.04)
>    configuration: --prefix=/home/pz9115/ffpo --disable-ffplay --arch=x64 
> --extra-cflags=-O3 --enable-static --target-os=linux
>    libavutil      60.  2.100 / 60.  2.100
>    libavcodec     62.  3.101 / 62.  3.101
>    libavformat    62.  0.102 / 62.  0.102
>    libavdevice    62.  0.100 / 62.  0.100
>    libavfilter    11.  0.100 / 11.  0.100
>    libswscale      9.  0.100 /  9.  0.100
>    libswresample   6.  0.100 /  6.  0.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 
> '/home/pz9115/mp/1080p_hevc_mp3.mp4':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      encoder         : Lavf60.16.100
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      genre           : Animation
>    Duration: 00:01:00.00, start: 0.000000, bitrate: 1564 kb/s
>    Stream #0:0[0x1](und): Video: hevc (Main) (hev1 / 0x31766568), 
> yuv420p(tv, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 1429 kb/s, 30 
> fps, 30 tbr, 15360 tbn (default)
>      Metadata:
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 libx265
>    Stream #0:1[0x2](und): Audio: mp3 (mp3float) (mp4a / 0x6134706D), 
> 48000 Hz, stereo, fltp, 128 kb/s (default)
>      Metadata:
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
> Stream mapping:
>    Stream #0:0 -> #0:0 (hevc (native) -> wrapped_avframe (native))
>    Stream #0:1 -> #0:1 (mp3 (mp3float) -> pcm_s16le (native))
> Press [q] to stop, [?] for help
> Output #0, null, to 'pipe:':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      genre           : Animation
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      encoder         : Lavf62.0.102
>    Stream #0:0(und): Video: wrapped_avframe, yuv420p(tv, progressive), 
> 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 30 fps, 30 tbn (default)
>      Metadata:
>        encoder         : Lavc62.3.101 wrapped_avframe
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>    Stream #0:1(und): Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s 
> (default)
>      Metadata:
>        encoder         : Lavc62.3.101 pcm_s16le
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
> [out#0/null @ 0x565233669eb0] video:731KiB audio:11250KiB subtitle:0KiB 
> other streams:0KiB global headers:0KiB muxing overhead: unknown
> frame= 1800 fps=635 q=-0.0 Lsize=N/A time=00:01:00.00 bitrate=N/A 
> speed=21.2x elapsed=0:00:02.83
> bench: utime=11.324s stime=0.290s rtime=2.834s
> bench: maxrss=186556KiB
> ```
> 
> Without patch(here I add the fno-tree-vectorize directly):
> 
> ./ffmpeg -benchmark -i ~/mp/1080p_hevc_mp3.mp4 -f null -
> ffmpeg version N-119636-g96518c8d8d Copyright (c) 2000-2025 the FFmpeg 
> developers
>    built with gcc 13 (Ubuntu 13.3.0-6ubuntu2~24.04)
>    configuration: --prefix=/home/pz9115/ffpo --disable-ffplay --arch=x64 
> --extra-cflags='-O3 -fno-tree-vectorize' --enable-static --target-os=linux
>    libavutil      60.  2.100 / 60.  2.100
>    libavcodec     62.  3.101 / 62.  3.101
>    libavformat    62.  0.102 / 62.  0.102
>    libavdevice    62.  0.100 / 62.  0.100
>    libavfilter    11.  0.100 / 11.  0.100
>    libswscale      9.  0.100 /  9.  0.100
>    libswresample   6.  0.100 /  6.  0.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 
> '/home/pz9115/mp/1080p_hevc_mp3.mp4':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      encoder         : Lavf60.16.100
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      genre           : Animation
>    Duration: 00:01:00.00, start: 0.000000, bitrate: 1564 kb/s
>    Stream #0:0[0x1](und): Video: hevc (Main) (hev1 / 0x31766568), 
> yuv420p(tv, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 1429 kb/s, 30 
> fps, 30 tbr, 15360 tbn (default)
>      Metadata:
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 libx265
>    Stream #0:1[0x2](und): Audio: mp3 (mp3float) (mp4a / 0x6134706D), 
> 48000 Hz, stereo, fltp, 128 kb/s (default)
>      Metadata:
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
> Stream mapping:
>    Stream #0:0 -> #0:0 (hevc (native) -> wrapped_avframe (native))
>    Stream #0:1 -> #0:1 (mp3 (mp3float) -> pcm_s16le (native))
> Press [q] to stop, [?] for help
> Output #0, null, to 'pipe:':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      genre           : Animation
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      encoder         : Lavf62.0.102
>    Stream #0:0(und): Video: wrapped_avframe, yuv420p(tv, progressive), 
> 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 30 fps, 30 tbn (default)
>      Metadata:
>        encoder         : Lavc62.3.101 wrapped_avframe
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>    Stream #0:1(und): Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s 
> (default)
>      Metadata:
>        encoder         : Lavc62.3.101 pcm_s16le
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
> [out#0/null @ 0x55eb196b7eb0] video:731KiB audio:11250KiB subtitle:0KiB 
> other streams:0KiB global headers:0KiB muxing overhead: unknown
> frame= 1800 fps=509 q=-0.0 Lsize=N/A time=00:01:00.00 bitrate=N/A 
> speed=  17x elapsed=0:00:03.53
> bench: utime=21.544s stime=0.349s rtime=3.536s
> bench: maxrss=181580KiB
> 
> And I also tested on a RISC-V develop board MUSE Pi Pro, Here following 
> is the configure and result:
> 
> Using patch:
> 
> root@spacemit-k1-x-MUSE-Pi-Pro-board:~# ./ffpv/bin/ffmpeg -benchmark -i 
> 1080p_hevc_mp3.mp4 -f null -
> ffmpeg version n6.1.2 Copyright (c) 2000-2024 the FFmpeg developers
>    built with gcc 16.0.0 (g3fc902e738b) 20250519 (experimental)
>    configuration: --prefix=/home/pz9115/ffpv --disable-ffplay 
> --arch=riscv --extra-cflags='-march=rv64gcv_zba_zbb_zbs -O3 -ffast-math' 
> --cross-prefix=/home/pz9115/rvv/bin/riscv64-unknown-linux-gnu- 
> --cc=/home/pz9115/rvv/bin/riscv64-unknown-linux-gnu-gcc 
> --cxx=/home/pz9115/rvv/bin/riscv64-unknown-linux-gnu-g++ --enable-static 
> --enable-cross-compile --target-os=linux --disable-rvv
>    libavutil      58. 29.100 / 58. 29.100
>    libavcodec     60. 31.102 / 60. 31.102
>    libavformat    60. 16.100 / 60. 16.100
>    libavdevice    60.  3.100 / 60.  3.100
>    libavfilter     9. 12.100 /  9. 12.100
>    libswscale      7.  5.100 /  7.  5.100
>    libswresample   4. 12.100 /  4. 12.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1080p_hevc_mp3.mp4':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      encoder         : Lavf60.16.100
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      genre           : Animation
>    Duration: 00:01:00.00, start: 0.000000, bitrate: 1564 kb/s
>    Stream #0:0[0x1](und): Video: hevc (Main) (hev1 / 0x31766568), 
> yuv420p(tv, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 1429 kb/s, 30 
> fps, 30 tbr, 15360 tbn (default)
>      Metadata:
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 libx265
>    Stream #0:1[0x2](und): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, 
> stereo, fltp, 128 kb/s (default)
>      Metadata:
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
> Stream mapping:
>    Stream #0:0 -> #0:0 (hevc (native) -> wrapped_avframe (native))
>    Stream #0:1 -> #0:1 (mp3 (mp3float) -> pcm_s16le (native))
> Press [q] to stop, [?] for help
> Odd rotation angle.
> If you want to help, upload a sample of this file to 
> https://streams.videolan.org/upload/ and contact the ffmpeg-devel 
> mailing list. (ffmpeg-devel@ffmpeg.org)Output #0, null, to 'pipe:':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      genre           : Animation
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      encoder         : Lavf60.16.100
>    Stream #0:0(und): Video: wrapped_avframe, yuv420p(tv, progressive), 
> 1080x1920 [SAR 1:1 DAR 9:16], q=2-31, 200 kb/s, 30 fps, 30 tbn (default)
>      Metadata:
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 wrapped_avframe
>    Stream #0:1(und): Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s 
> (default)
>      Metadata:
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 pcm_s16le
> [out#0/null @ 0x28a82e0] video:844kB audio:11250kB subtitle:0kB other 
> streams:0kB global headers:0kB muxing overhead: unknown
> frame= 1800 fps= 42 q=-0.0 Lsize=N/A time=00:00:59.97 bitrate=N/A 
> speed=1.41x
> bench: utime=207.150s stime=5.319s rtime=42.608s
> bench: maxrss=162160kB
> 
> Without patch(same added the fno-tree-vectorize directly):
> 
> ./ffp/bin/ffmpeg -benchmark -i 1080p_hevc_mp3.mp4 -f null -
> ffmpeg version n6.1.2 Copyright (c) 2000-2024 the FFmpeg developers
>    built with gcc 16.0.0 (g38163c874a3-dirty) 20250515 (experimental)
>    configuration: --prefix=/home/pz9115/ffp --disable-ffplay 
> --arch=riscv --sysroot=/home/pz9115/rv/sysroot 
> --extra-cflags='-march=rv64gcv_zba_zbb_zbc_zbs_zca_zcd -mabi=lp64d -O3 
> -fno-tree-vectorize -static' --extra-ldflags=-static 
> --cross-prefix=/home/pz9115/rv/bin/riscv64-unknown-linux-gnu- 
> --enable-static --enable-cross-compile --target-os=linux --disable-rvv
>    libavutil      58. 29.100 / 58. 29.100
>    libavcodec     60. 31.102 / 60. 31.102
>    libavformat    60. 16.100 / 60. 16.100
>    libavdevice    60.  3.100 / 60.  3.100
>    libavfilter     9. 12.100 /  9. 12.100
>    libswscale      7.  5.100 /  7.  5.100
>    libswresample   4. 12.100 /  4. 12.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1080p_hevc_mp3.mp4':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      encoder         : Lavf60.16.100
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      genre           : Animation
>    Duration: 00:01:00.00, start: 0.000000, bitrate: 1564 kb/s
>    Stream #0:0[0x1](und): Video: hevc (Main) (hev1 / 0x31766568), 
> yuv420p(tv, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 1429 kb/s, 30 
> fps, 30 tbr, 15360 tbn (default)
>      Metadata:
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 libx265
>    Stream #0:1[0x2](und): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, 
> stereo, fltp, 128 kb/s (default)
>      Metadata:
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
> Stream mapping:
>    Stream #0:0 -> #0:0 (hevc (native) -> wrapped_avframe (native))
>    Stream #0:1 -> #0:1 (mp3 (mp3float) -> pcm_s16le (native))
> Press [q] to stop, [?] for help
> Output #0, null, to 'pipe:':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 512
>      compatible_brands: isomiso2mp41
>      title           : Big Buck Bunny, Sunflower version
>      artist          : Blender Foundation 2008, Janus Bager Kristensen 2013
>      composer        : Sacha Goedegebure
>      genre           : Animation
>      comment         : Creative Commons Attribution 3.0 - 
> http://bbb3d.renderfarming.net
>      encoder         : Lavf60.16.100
>    Stream #0:0(und): Video: wrapped_avframe, yuv420p(tv, progressive), 
> 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 30 fps, 30 tbn (default)
>      Metadata:
>        handler_name    : GPAC ISO Video Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 wrapped_avframe
>    Stream #0:1(und): Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s 
> (default)
>      Metadata:
>        handler_name    : GPAC ISO Audio Handler
>        vendor_id       : [0][0][0][0]
>        encoder         : Lavc60.31.102 pcm_s16le
> [out#0/null @ 0x2729630] video:844kB audio:11250kB subtitle:0kB other 
> streams:0kB global headers:0kB muxing overhead: unknown
> frame= 1800 fps= 30 q=-0.0 Lsize=N/A time=00:00:59.97 bitrate=N/A 
> speed=   1x
> bench: utime=321.145s stime=2.475s rtime=59.960s
> bench: maxrss=131532kB
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The RISC-V autovectorised output looks like it has a warning "Odd
rotation angle" which is not present in the non-autovectorised output.

-- 
Frank

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