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c05fc27dd3
Extensions in AAC USAC can be stored across multiple frames (mainly to keep CBR compliance). This means that we need to reallocate a buffer when new data is received, accumulate the bitstream data, and so on until the end of extension flag is signalled and the extension can be decoded. This is made more complicated by the way in which the AAC channel layout switching is performed. After decades of evolution, our AAC decoder evolved to double-buffer its entire configuration. All changes are buffered, verified, and applied, on a per-frame basis if required, in often random order. Since we allocate the extension data on heap, this means that if configuration is applied, in order to avoid double-freeing, we have to keep track of what we've allocated. It should be noted that extensions which are spread in multiple frames are generally rare, so an optimization to introduce av_refstruct_realloc() wouldn't generally be useful across the codebase. Therefore, a copy is good enough for now. Thanks to Michael Niedermayer for additional fixing. Fixes: double free Fixes: 393523547/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AAC_LATM_fuzzer-6740617236905984 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
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.