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0166b1d1a6
The Winnov WNV1 format is designed for a little-endian bitstream reader; yet our decoder reversed every byte bitwise (in a buffer only allocated for this purpose) to use a big-endian bitstream reader. This commit stops this. Two things needed to be done to achieve this: The codes in the table used to initialize a VLC reader needed to be reversed bitwise (when initializing a VLC in LE mode, it is expected that the first bit to be read is in the least significant bit; with BE codes the first bit to be read is the most significant bit of the code) and the following expression needed to be adapted: ff_reverse[get_bits(&w->gb, 8 - w->shift)] But this is easy: When only the bits read are reversed, they coincide with what a little-endian bitstream reader reads that reads the original, not-reversed data. But ff_reverse always reverses the full eight bits and this also performs a shift by (8 - (8 - w->shift)) on top of reversing the bits read. So the above line needs to be changed to get_bits(&w->gb, 8 - w->shift) << w->shift and this also shows why the variable shift is named the way it is. Finally, this also fixes a hypothetical memleak: For gigantic packets, initializing a GetBitContext can fail and in this case, the buffer containing the reversed data would leak. Reviewed-by: Paul B Mahol <onemda@gmail.com> 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.