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Ramiro Polla 384fe39623 swscale/range_convert: fix mpeg ranges in yuv range conversion for non-8-bit pixel formats 
There is an issue with the constants used in YUV to YUV range conversion,
where the upper bound is not respected when converting to mpeg range.

With this commit, the constants are calculated at runtime, depending on
the bit depth. This approach also allows us to more easily understand how
the constants are derived.

For bit depths <= 14, the number of fixed point bits has been set to 14
for all conversions, to simplify the code.
For bit depths > 14, the number of fixed points bits has been raised and
set to 18, to allow for the conversion to be accurate enough for the mpeg
range to be respected.

The convert functions now take the conversion constants (coeff and offset)
as function arguments.
For bit depths <= 14, coeff is unsigned 16-bit and offset is 32-bit.
For bit depths > 14, coeff is unsigned 32-bit and offset is 64-bit.

x86_64:
chrRangeFromJpeg8_1920_c:    2127.4   2125.0  (1.00x)
chrRangeFromJpeg16_1920_c:   2325.2   2127.2  (1.09x)
chrRangeToJpeg8_1920_c:      3166.9   3168.7  (1.00x)
chrRangeToJpeg16_1920_c:     2152.4   3164.8  (0.68x)
lumRangeFromJpeg8_1920_c:    1263.0   1302.5  (0.97x)
lumRangeFromJpeg16_1920_c:   1080.5   1299.2  (0.83x)
lumRangeToJpeg8_1920_c:      1886.8   2112.2  (0.89x)
lumRangeToJpeg16_1920_c:     1077.0   1906.5  (0.56x)

aarch64 A55:
chrRangeFromJpeg8_1920_c:   28835.2  28835.6  (1.00x)
chrRangeFromJpeg16_1920_c:  28839.8  32680.8  (0.88x)
chrRangeToJpeg8_1920_c:     23074.7  23075.4  (1.00x)
chrRangeToJpeg16_1920_c:    17318.9  24996.0  (0.69x)
lumRangeFromJpeg8_1920_c:   15389.7  15384.5  (1.00x)
lumRangeFromJpeg16_1920_c:  15388.2  17306.7  (0.89x)
lumRangeToJpeg8_1920_c:     19227.8  19226.6  (1.00x)
lumRangeToJpeg16_1920_c:    15387.0  21146.3  (0.73x)

aarch64 A76:
chrRangeFromJpeg8_1920_c:    6324.4   6268.1  (1.01x)
chrRangeFromJpeg16_1920_c:   6339.9  11521.5  (0.55x)
chrRangeToJpeg8_1920_c:      9656.0   9612.8  (1.00x)
chrRangeToJpeg16_1920_c:     6340.4  11651.8  (0.54x)
lumRangeFromJpeg8_1920_c:    4422.0   4420.8  (1.00x)
lumRangeFromJpeg16_1920_c:   4420.9   5762.0  (0.77x)
lumRangeToJpeg8_1920_c:      5949.1   5977.5  (1.00x)
lumRangeToJpeg16_1920_c:     4446.8   5946.2  (0.75x)

NOTE: all simd optimizations for range_convert have been disabled.
      they will be re-enabled when they are fixed for each architecture.

NOTE2: the same issue still exists in rgb2yuv conversions, which is not
       addressed in this commit.
2024-12-05 21:10:29 +01:00
compat compat: Fix the fallback definition of stdc_trailing_zeros 2024-09-24 14:00:27 +03:00
doc avutil/csp: add EOTF function definitions 2024-12-05 12:27:32 +01:00
ffbuild configure: Add wasm as a fake arch 2024-12-04 16:43:06 +08:00
fftools fftools/ffmpeg_sched: signal the main thread when a task fails 2024-11-25 05:26:49 +01:00
libavcodec avcodec/hevc: Add wasm simd128 idct 2024-12-04 16:43:07 +08:00
libavdevice avdevice/dshow: fix unused variable warning 2024-10-17 13:04:17 +02:00
libavfilter avfilter/asrc_sine: increase frequency accuracy 2024-11-29 21:16:22 +01:00
libavformat avformat/mov: add support for pssh box 2024-12-05 14:22:16 -03:00
libavutil avutil/tests/color_utils: add tests for av_csp_itu_eotf 2024-12-05 12:27:33 +01:00
libpostproc */version.h: bump after release/7.1 branch 2024-09-24 17:10:35 +02:00
libswresample arm: Consistently use proper interworking function returns 2024-10-09 15:52:51 +03:00
libswscale swscale/range_convert: fix mpeg ranges in yuv range conversion for non-8-bit pixel formats 2024-12-05 21:10:29 +01:00
presets
tests swscale/range_convert: fix mpeg ranges in yuv range conversion for non-8-bit pixel formats 2024-12-05 21:10:29 +01:00
tools tools/general_assembly: exclude Derek from GA emails 2024-11-28 15:51:37 +01:00
.gitattributes lavf/assenc: normalize line endings to \n 2024-02-11 17:01:07 -08:00
.gitignore .gitignore: add exclusions for shader .c files 2024-11-18 07:54:21 +01:00
.mailmap mailmap: add entry for myself 2024-07-15 01:59:37 +02:00
Changelog lavc: deprecate the omx encoders 2024-11-09 02:46:17 +01:00
configure configure: Add wasm as a fake arch 2024-12-04 16:43:06 +08:00
CONTRIBUTING.md
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
INSTALL.md INSTALL: explain the circular dependency issue and solution 2024-11-03 19:35:23 +01:00
LICENSE.md
MAINTAINERS MAINTAINERS: Lauri is still available but is really low on time nowadays 2024-11-28 23:19:00 +01:00
Makefile configure: Add wasm as a fake arch 2024-12-04 16:43:06 +08:00
README.md
RELEASE RELEASE: update release number after release/7.1 branch 2024-10-09 01:55:50 +02:00

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.