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Commit 1a29804558c13ef512d9ef73a9b0d782af4fa5f2 guarded several initializations of static data in the AAC decoders with an AVOnce and set the FF_CODEC_CAP_INIT_THREADSAFE flag, believing the former to be sufficient for the latter. It wasn't, because several of these static tables are shared with other components, so that there might be data races if they are initialized from multiple threads. This affected initializing the ff_sine_* tables as well as initializing the ff_aac_pow*sf_tab tables (shared between both decoders and encoder) as well as ff_aac_kbd_* tables (shared between encoder and floating point decoder). Commit 3d62e7a30fa552be52d12b31e3e0f79153aff891 set the FF_CODEC_CAP_INIT_THREADSAFE flag for the AAC encoder. More explicitly, this commit used the same AVOnce to guard initializing ff_aac_pow*sf_tab in the encoder and to guard initializing the static data of each decoder; the ensuing catastrophe was "fixed" in commit ec0719264cb9a9d5cbaf225da48929aea24997a3 by using a single AVOnce for each codec again. But the codec cap has not been removed and therefore the encoder claimed to be init-threadsafe, but wasn't, because of the same tables as above. The ff_sine_* tables as well as ff_aac_pow*sf_tab tables have already been fixed; this commit deals with the ff_aac_kbd_* tables, making the encoder as well as the floating-point decoder init-threadsafe (the fixed-point decoder is it already). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@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.
- 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.