[FFmpeg-trac] #9744(avfilter:new): blend=grainextract doesn't work

[FFmpeg]

#9744: blend=grainextract doesn't work
-------------------------------------+-------------------------------------
             Reporter:  Michael      |                     Type:  defect
  Koch                               |
               Status:  new          |                 Priority:  normal
            Component:  avfilter     |                  Version:  git-
                                     |  master
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 blend=grainextract should calculate the difference between two frames and
 shift the result to middle gray. If both frames are identical, the result
 should be uniform middle gray. But it isn't.

 ffmpeg -f lavfi -i testsrc2 -lavfi split,blend=grainextract -frames 1 -y
 out.png


 ffmpeg version 2022-04-18-git-d5687236ab-full_build-www.gyan.dev Copyright
 (c) 2000-2022 the FFmpeg developers
   built with gcc 11.2.0 (Rev10, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 w32threads --disable-autodetect --enable-fontconfig --enable-iconv
 --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma
 --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt
 --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray
 --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libdavs2
 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1
 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2
 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx
 --enable-mediafoundation --enable-libass --enable-frei0r --enable-
 libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab
 --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm
 --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-
 d3d11va --enable-dxva2 --enable-libmfx --enable-libshaderc --enable-vulkan
 --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme
 --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb
 --enable-libmp3lame --enable-libshine --enable-libtheora --enable-
 libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm
 --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-
 libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-
 libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
   libavutil      57. 24.101 / 57. 24.101
   libavcodec     59. 26.100 / 59. 26.100
   libavformat    59. 22.100 / 59. 22.100
   libavdevice    59.  6.100 / 59.  6.100
   libavfilter     8. 33.100 /  8. 33.100
   libswscale      6.  6.100 /  6.  6.100
   libswresample   4.  6.100 /  4.  6.100
   libpostproc    56.  5.100 / 56.  5.100
 Input #0, lavfi, from 'testsrc2':
   Duration: N/A, start: 0.000000, bitrate: N/A
   Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 320x240 [SAR
 1:1 DAR 4:3], 25 tbr, 25 tbn
 Stream mapping:
   Stream #0:0 (rawvideo) -> split:default
   blend:default -> Stream #0:0 (png)
 Press [q] to stop, [?] for help
 Output #0, image2, to 'out.png':
   Metadata:
     encoder         : Lavf59.22.100
   Stream #0:0: Video: png, rgb24(pc, gbr/unknown/unknown, progressive),
 320x240 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 25 fps, 25 tbn
     Metadata:
       encoder         : Lavc59.26.100 png
 frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
 speed=4.33x
 video:4kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: unknown
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9744>
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