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2589ce4a2c
Otherwise, we always pass frames that already have buffers allocated, which
breaks the no-op refcopy optimizations.
Testing with -p 0.1 -threads 16 -bench 10, on an AMD Ryzen 9 9950X3D:
Before:
Overall speedup=2.776x faster, min=0.133x max=629.496x
yuv444p 1920x1080 -> yuv444p 1920x1080, flags=0x100000 dither=1
time=9 us, ref=9 us, speedup=1.043x faster
After:
Overall speedup=2.721x faster, min=0.140x max=574.034x
yuv444p 1920x1080 -> yuv444p 1920x1080, flags=0x100000 dither=1
time=0 us, ref=28 us, speedup=516.504x faster
(The slowdown in the legacy swscale case is from swscale's lack of a no-op
refcopy optimizaton, plus the fact that it's now actually doing memory
work instead of a no-op / redundant memset)
Signed-off-by: Niklas Haas <git@haasn.dev>
FFmpeg README
FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.
Libraries
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides means to alter decoded audio and video through a directed graph of connected filters.libavdeviceprovides an abstraction to access capture and playback devices.libswresampleimplements audio mixing and resampling routines.libswscaleimplements 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,ismindexandqt-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.