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7bd3b73716
This already fixes a race in the vp9-encparams test. In this test, side data is added to the current frame after having been decoded (and therefore after ff_thread_finish_setup() has been called). Yet the update_thread_context callback called ff_thread_ref_frame() and therefore av_frame_ref() with this frame as source frame and the ensuing read was unsynchronised with adding the side data, i.e. there was a data race. By switching to the ProgressFrame API the implicit av_frame_ref() is removed and the race fixed except if this frame is later reused by a show-existing-frame which uses an explicit av_frame_ref(). The vp9-encparams test does not cover this, so this commit already fixes all the races in this test. This decoder kept multiple references to the same ThreadFrames in the same context and therefore had lots of implicit av_frame_ref() even when decoding single-threaded. This incurred lots of small allocations: When decoding an ordinary 10s video in single-threaded mode the number of allocations reported by Valgrind went down from 57,814 to 20,908; for 10 threads it went down from 84,223 to 21,901. Reviewed-by: Anton Khirnov <anton@khirnov.net> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.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 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.