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db8b450ebb
interleaved_yuv_to_planar, shared by uyvytoyuv422, uyvytoyuv420,
yuyvtoyuv422 and yuyvtoyuv420, only handled even widths. The packed
UYVY/YUYV macroblocks are pixel pairs and the trailing half macroblock of
an odd width was mishandled:
- the slow path (width <= 31) decrements its pixel counter by two from an
odd value, so it never reaches zero and the loop runs far past the line,
overwriting the destination (observed as a crash in checkasm);
- the fast path (width >= 32) shifts the tail pointers back by width-32 and
reprocesses an overlapping, misaligned tuple, producing wrong samples and
dropping the last chroma column.
Process only whole pixel pairs and emit the trailing odd column from a
per-line epilogue that matches the C reference: for yuv422 one Y, U and V
sample; for yuv420 the Y of both lines of the pair with the chroma averaged
across them, and luma only for the final line when the height is odd. The
empty even part (width 0 or 1) is guarded so the slow path no longer enters
its run-past loop.
All four variants are now bit-exact with the C reference for even and odd
widths. Verified with checkasm under qemu-aarch64.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit a554d0aa8a)
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 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.