[FFmpeg-trac] #9977(avfilter:new): ELBG Posterizer creates flickering effect

[FFmpeg]

#9977: ELBG Posterizer creates flickering effect
----------------------------------+--------------------------------------
             Reporter:  erjiang   |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avfilter  |                  Version:  git-master
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
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 At some point the ELBG filter changed, and now creates a flickering effect
 that it did not use to create. The below example renders a video where the
 black color sometimes appears and sometimes does not.

 {{{
 $ ffmpeg -version
 ffmpeg version N-63101-gc92edd969a-static
 https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2022 the FFmpeg
 developers
 built with gcc 8 (Debian 8.3.0-6)
 configuration: --enable-gpl --enable-version3 --enable-static --disable-
 debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio
 --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp
 --enable-libgme --enable-gray --enable-libaom --enable-libfribidi
 --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame
 --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
 --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt
 --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab
 --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264
 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid
 --enable-libzvbi --enable-libzimg
 libavutil      57. 36.101 / 57. 36.101
 libavcodec     59. 42.104 / 59. 42.104
 libavformat    59. 30.101 / 59. 30.101
 libavdevice    59.  8.101 / 59.  8.101
 libavfilter     8. 48.100 /  8. 48.100
 libswscale      6.  8.108 /  6.  8.108
 libswresample   4.  9.100 /  4.  9.100
 libpostproc    56.  7.100 / 56.  7.100
 $ ffmpeg -i Jane_M._Byrne_Interchange_Traffic_1080p.webm -vf
 elbg=codebook_length=3:nb_steps=2 output-new.mp4 2> stderr.log 1>
 stdout.log
 }}}

 Source video file can be downloaded from: https://invent.kde.org/erjiang
 /kdenlive-
 backcompat/-/blob/master/projects/footage/Jane_M._Byrne_Interchange_Traffic_1080p.webm

 ffmpeg 4.4.2 with libavfilter=7.110.100 is known to work (doesn’t have the
 flickering).
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9977>
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