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OvchinnikovDmitrii c13d959343 lavc/libvpx: increase thread limit to 64 
This change improves the performance and multicore scalability of the vp9
codec for streaming single-pass encoded videos by taking advantage of up
to 64 cores in the system. The current thread limit for ffmpeg codecs is 16
(MAX_AUTO_THREADS in pthread_internal.h) due to a limitation in H.264 codec
that prevents more than 16 threads being used.

Experiments show that increasing the thread limit to 64 for vp9 improves
the performance for encoding 4K raw videos for streaming by up to 47%
compared to 16 threads, and from 20-30% for 32 threads, with the same quality
as measured by the VMAF score.

Rationale for this change:
Vp9 uses tiling to split the video frame into multiple columns; tiles must
be at least 256 pixels wide, so there is a limit to how many tiles can be
used. The tiles can be processed in parallel, and more tiles mean more CPU
threads can be used. 4K videos can make use of 16 threads, and 8K videos
can use 32. Row-mt can double the number of threads so 64 threads can be used.

Signed-off-by: James Zern <jzern@google.com>
2023-01-17 14:02:55 -08:00
compat compat/cuda: switch from powf to __powf intrinsic 2022-09-03 20:27:34 +02:00
doc avfilter: add fractional delay IR source filter 2023-01-16 09:59:31 +01:00
ffbuild configure: probe RISC-V Vector extension 2022-09-27 13:19:52 +02:00
fftools ffprobe: expose AVAmbientViewingEnvironment side data in AVFrames 2023-01-13 21:26:27 +02:00
libavcodec lavc/libvpx: increase thread limit to 64 2023-01-17 14:02:55 -08:00
libavdevice avdevice/avfoundation: convert to new channel layout-API 2022-11-08 14:08:05 -03:00
libavfilter avfilter/vf_lagfun: call av_frame_copy_props() 2023-01-17 22:55:14 +01:00
libavformat avformat/segment: calculate segment durations correctly. 2023-01-16 15:37:59 +05:30
libavutil avutil: introduce AVAmbientViewingEnvironment side data 2023-01-13 21:26:13 +02:00
libpostproc postproc/postprocess_template: Fix alignment 2022-11-09 17:39:00 +01:00
libswresample swresample/swresample_frame: fix regression in detecting changes 2023-01-04 18:19:07 +01:00
libswscale swscale/utils: Fix indentation 2022-11-24 21:02:57 +01:00
presets
tests avformat/segment: calculate segment durations correctly. 2023-01-16 15:37:59 +05:30
tools tools/target_dec_fuzzer: Adjust threshold for RSCC 2022-12-01 21:43:57 +01:00
.gitattributes fate: add SCC test 2017-01-27 17:06:42 +01:00
.gitignore gitignore: add config_components.h 2022-03-17 18:35:41 -03:00
.mailmap mailmap: stop git lying about who I commit things as 2022-11-04 19:37:46 +01:00
.travis.yml Merge commit '899ee03088d55152a48830df0899887f055da1de' 2019-03-14 15:53:16 -03:00
Changelog avfilter: add fractional delay IR source filter 2023-01-16 09:59:31 +01:00
configure avcodec/vaapi_encode_h26x: passthrough A53 CC data as H264/HEVC SEI 2023-01-17 10:10:52 +08:00
CONTRIBUTING.md Add CONTRIBUTING.md 2016-09-18 10:02:13 +01:00
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
INSTALL.md INSTALL.md: Fix Markdown formatting 2019-01-31 10:29:16 -09:00
LICENSE.md avfilter/vf_geq: Relicense to LGPL 2019-12-28 11:20:48 +01:00
MAINTAINERS MAINTAINERS: add myself as amfenc* maintainer 2022-11-10 16:28:07 +01:00
Makefile configure: probe RISC-V Vector extension 2022-09-27 13:19:52 +02:00
README.md README: fix typo and description of libavfilter 2021-10-08 09:44:34 +05:30
RELEASE RELEASE: update after 5.1 branch 2022-07-13 00:31:42 +02:00

README.md

FFmpeg README

FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.

Libraries

  • libavcodec provides implementation of a wider range of codecs.
  • libavformat implements streaming protocols, container formats and basic I/O access.
  • libavutil includes hashers, decompressors and miscellaneous utility functions.
  • libavfilter provides means to alter decoded audio and video through a directed graph of connected filters.
  • libavdevice provides an abstraction to access capture and playback devices.
  • libswresample implements audio mixing and resampling routines.
  • libswscale implements color conversion and scaling routines.

Tools

  • ffmpeg is a command line toolbox to manipulate, convert and stream multimedia content.
  • ffplay is a minimalistic multimedia player.
  • ffprobe is a simple analysis tool to inspect multimedia content.
  • Additional small tools such as aviocat, ismindex and qt-faststart.

Documentation

The offline documentation is available in the doc/ directory.

The online documentation is available in the main website and in the wiki.

Examples

Coding examples are available in the doc/examples directory.

License

FFmpeg codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.

Contributing

Patches should be submitted to the ffmpeg-devel mailing list using git format-patch or git send-email. Github pull requests should be avoided because they are not part of our review process and will be ignored.