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1957095e80
Fixes: Timeout (too long -> 241ms)
Fixes: 29083/clusterfuzz-testcase-minimized-ffmpeg_dem_SWF_fuzzer-6273684478230528
The source of the magic number is
A very quick simulation of the best case compression for "compress"
below is not nice written code as i did not expect I or anyone else
would ever see it again
I would have preferred some nicer expression or course, but thats
what it seems to be asymptotically. For smaller amounts of data a
tighter bound is possible but i saw no nice way to consider that
and it seems also overkill to try to do it more fine grained for
just this
main(){
int64_t bits = 0;
int bank = 256;
int bitbank = 8;
for(unsigned i = 0; i<1024*1024*1024*4U-100000;) {
int word_size = bank-255;
i += word_size;
bits += bitbank;
if (!(bank & (bank-1)))
bitbank ++;
bank++;
if (bitbank > 16) {
printf("BEST %f \n", 8.0 * i / bits );
bank = 256;
bitbank = 8;
}
}
}
above assumes i remembered correctly how the algorithm works but the
value was close to what actual compession of zeros gave
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
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.