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fuchsia / third_party / ffmpeg / upstream/master
commit89f984e3d1d8f1f009c616e0c6425094395fdbdc[log] [tgz]
authorAndreas Rheinhardt <andreas.rheinhardt@outlook.com>Wed Nov 26 20:15:55 2025 +0100
committerAndreas Rheinhardt <andreas.rheinhardt@outlook.com>Sun Nov 30 00:15:43 2025 +0100
tree2d13b1708e87c2cfb4b7c200e9630f3d1941fc59
parente6ae2802a39b24324bd6c394c073a26900a39f23 [diff]
avcodec/x86/h264_idct: Fix ff_h264_luma_dc_dequant_idct_sse2 checkasm failures

ff_h264_luma_dc_dequant_idct_sse2() does not pass checkasm for certain
seeds, because the input to packssdw no longer fits into an int16_t,
leading to saturation, where the C code just truncates. I don't know
whether the spec contains provisions that ensure that valid input
must not exceed 16 bit or whether the such inputs (even if invalid)
can be triggered by the actual code and not only the test.

This commit adapts the behavior of the function to the C reference code
to fix the test. packssdw is avoided, instead the lower words are
directly transfered to GPRs to be written out. This has unfortunately
led to a slight performance regression here (14.5 vs 15.1 cycles).

Fixes issue #20835.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
1 file changed
tree: 2d13b1708e87c2cfb4b7c200e9630f3d1941fc59
  1. .forgejo/
  2. compat/
  3. doc/
  4. ffbuild/
  5. fftools/
  6. libavcodec/
  7. libavdevice/
  8. libavfilter/
  9. libavformat/
  10. libavutil/
  11. libswresample/
  12. libswscale/
  13. presets/
  14. tests/
  15. tools/
  16. .gitattributes
  17. .gitignore
  18. .mailmap
  19. Changelog
  20. configure
  21. CONTRIBUTING.md
  22. COPYING.GPLv2
  23. COPYING.GPLv3
  24. COPYING.LGPLv2.1
  25. COPYING.LGPLv3
  26. CREDITS
  27. FUNDING.json
  28. INSTALL.md
  29. LICENSE.md
  30. MAINTAINERS
  31. Makefile
  32. README.md
  33. RELEASE
README.md

FFmpeg README

FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.

Libraries

  • libavcodec provides implementation of a wider range of codecs.
  • libavformat implements streaming protocols, container formats and basic I/O access.
  • libavutil includes hashers, decompressors and miscellaneous utility functions.
  • libavfilter provides means to alter decoded audio and video through a directed graph of connected filters.
  • libavdevice provides an abstraction to access capture and playback devices.
  • libswresample implements audio mixing and resampling routines.
  • libswscale implements 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, ismindex and qt-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.