[FFmpeg-trac] #8779(ffmpeg:new): Zscale transform to ST 2084 EOTF results in black video output
FFmpeg
trac at avcodec.org
Tue Jul 7 23:44:05 EEST 2020
#8779: Zscale transform to ST 2084 EOTF results in black video output
-------------------------------------+-------------------------------------
Reporter: zambelli | Type: defect
Status: new | Priority: important
Component: ffmpeg | Version: git-
Keywords: zscale, | master
libzimg, z.lib, smpte2084, | Blocked By:
st2084, hdr |
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
== Summary of the bug: ==
Sometime between releases 4.2.2 and 4.2.3 a bug was introduced into Zscale
filter which causes the video output of the filter to be reduced to black
when transforming video using SMPTE ST 2084 (PQ) EOTF.
== How to reproduce: ==
Source video:
https://hulu.box.com/shared/static/5o419x2dag93wx5f0msc69gbljfydri1.mp4
ffmpeg version git-2020-06-28-4cfcfb3
built with gcc 9.3.1 (GCC) 20200621
{{{
ffmpeg.exe -y -i zscale_test_source.mp4 -vf
zscale=t=linear:w=640:h=360,format=gbrpf32le,zscale=t=smpte2084:p=bt709:m=bt709,format=yuv420p10le
-vcodec ffv1 zscale_test_smpte2084.avi
}}}
Sample output:
https://hulu.box.com/shared/static/6a8yjs5mel2scv63vvpmrn0438fqbiil.avi
If t=smpte2084 is replaced with another EOTF, such as bt709, the filter
produces the correct output:
{{{
ffmpeg.exe -y -i zscale_test_source.mp4 -vf
zscale=t=linear:w=640:h=360,format=gbrpf32le,zscale=t=bt709:p=bt709:m=bt709,format=yuv420p10le
-vcodec ffv1 zscale_test_bt709.avi
}}}
Sample output:
https://hulu.box.com/shared/static/uuy3gfhg6mwflrqmhvb2bvkl7009nlf4.avi
The bug does not repro in FFmpeg release 4.2.2. To the best of my memory
while working with nightly builds, this Zscale transform worked correctly
until at least early May 2020.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8779>
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