68a0a164d1
filter_slice calls qsort, so qsort is in a performance critical position. AV_QSORT is substantially faster due to the inlining of the comparison callback. Thus, the increase in performance is worth the increase in binary size. Sample benchmark (x86-64, Haswell, GNU/Linux), filter-removegrain-mode-02 (from FATE) new: 24060 decicycles in qsort, 1 runs, 0 skips 15690 decicycles in qsort, 2 runs, 0 skips 9307 decicycles in qsort, 4 runs, 0 skips 5572 decicycles in qsort, 8 runs, 0 skips 3485 decicycles in qsort, 16 runs, 0 skips 2517 decicycles in qsort, 32 runs, 0 skips 1979 decicycles in qsort, 64 runs, 0 skips 1911 decicycles in qsort, 128 runs, 0 skips 1568 decicycles in qsort, 256 runs, 0 skips 1596 decicycles in qsort, 512 runs, 0 skips 1614 decicycles in qsort, 1024 runs, 0 skips 1874 decicycles in qsort, 2046 runs, 2 skips 2186 decicycles in qsort, 4094 runs, 2 skips old: 246960 decicycles in qsort, 1 runs, 0 skips 135765 decicycles in qsort, 2 runs, 0 skips 70920 decicycles in qsort, 4 runs, 0 skips 37710 decicycles in qsort, 8 runs, 0 skips 20831 decicycles in qsort, 16 runs, 0 skips 12225 decicycles in qsort, 32 runs, 0 skips 8083 decicycles in qsort, 64 runs, 0 skips 6270 decicycles in qsort, 128 runs, 0 skips 5321 decicycles in qsort, 256 runs, 0 skips 4860 decicycles in qsort, 512 runs, 0 skips 4424 decicycles in qsort, 1024 runs, 0 skips 4191 decicycles in qsort, 2046 runs, 2 skips 4934 decicycles in qsort, 4094 runs, 2 skips Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
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 a mean to alter decoded Audio and Video through chain of 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.
- ffserver is a multimedia streaming server for live broadcasts.
- 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. Few developers
follow pull requests so they will likely be ignored.