7 Commits

Author SHA1 Message Date
Ramiro Polla
4bee010844 swscale/range_convert: fix truncation bias in range conversion
384fe39623 introduced a regression in the
range conversion offset calculation, resulting in a slight green tint
in full-range RGB to YUV conversions of grayscale values.

The offset being calculated was not taking into consideration a bias
needed for correctly rounding the result from the multiplication stage,
leading to a truncated value.

Fixes issue #11646.
2025-11-06 20:36:08 +00:00
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
Michael Niedermayer
adfde9a646 avformat/avienc: Fix wrongly placed comment
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2015-03-19 17:30:28 +01:00
Michael Niedermayer
42801505cd tests: Add vsynth2 which uses the new reference.pnm
The file is already present in git and by using it we can perform more tests
without the need of fate samples

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2014-12-02 03:39:56 +01:00
Michael Niedermayer
ed49b142bb tests: Rename vsynth2 to vsynth_lena
This avoids confusion with a growing number of vsynth tests

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2014-12-02 03:02:30 +01:00
Carl Eugen Hoyos
e705d0ce1c Set dwSuggestBufferSize to largest chunk size for every stream in avi.
Fixes playback with WMP 9 for files with large (rawvideo) frames
as explained in ticket #2145.

Fixes ticket #2818.
2014-05-19 00:05:40 +02:00
Michael Niedermayer
7711f19eda Merge commit 'e816034a5fa131b13c4ad87bb0b5065b4f5697c6'
* commit 'e816034a5fa131b13c4ad87bb0b5065b4f5697c6':
  fate-seek: remove use of gnu make 3.82 only private modifier
  fate: move vsynth reference files to their own directory
  fate: move fate-acodec reference files to their own dir
  configure: avplay now depends on avresample
  fate: split dependencies for fate-seek tests

Conflicts:
	configure
	tests/fate/seek.mak

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2012-12-03 02:33:27 +01:00