[FFmpeg-trac] #8987(undetermined:new): zmq doesn't work in this filter chain

[FFmpeg]

#8987: zmq doesn't work in this filter chain
-------------------------------------+-------------------------------------
             Reporter:  mkoch        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:  zmq          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 This command line works as expected:

 ffmpeg -f lavfi -i testsrc2=s=1920x1080 -f lavfi -i color=gray:s=960x540
 -lavfi
 [0]zmq,scale at my=480:-1,chromakey at my=0x0000ff:0.35[FG];[1][FG]overlay,format=rgb24
 -f sdl -

 You can send zmq messages to the running ffmpeg process:
 echo scale at my w 240 | zmqsend
 or
 echo scale at my w 480 | zmqsend
 and you see that the size of the foreground video changes.
 So far, everything is working as expected.

 Now comes the problem. The only difference is that a "eq" filter (without
 any options) is inserted before the "chromakey" filter.

 ffmpeg -f lavfi -i testsrc2=s=1920x1080 -f lavfi -i color=gray:s=960x540
 -lavfi
 [0]zmq,scale at my=480:-1,eq,chromakey at my=0x0000ff:0.35[FG];[1][FG]overlay,format=rgb24
 -f sdl -

 When you now send the same messages as before, the size of the foreground
 video doesn't change.
 Same problem also if the messages aren't sent by the "zmqsend" tool, but
 instead by a C# program with "NetMQ" library.

 Below is the console output for the not-working case:

 C:\Users\astro\Desktop\FFbluescreen>ffmpeg -f lavfi -i
 testsrc2=s=1920x1080 -f lavfi -i color=gray:s=960x540 -lavfi
 [0]zmq,scale at my=480:-1,eq,chromakey at my=0x0000ff:0.35[FG];[1][FG]overlay,format=rgb24
 -f sdl -
 ffmpeg version 2020-11-11-git-89429cf2f2-full_build-www.gyan.dev Copyright
 (c) 2000-2020 the FFmpeg developers
   built with gcc 10.2.0 (Rev3, 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-lzma --enable-
 libsnappy --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq
 --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2
 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1
 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid
 --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass
 --enable-frei0r --enable-libfreetype --enable-libfribidi --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-libglslang
 --enable-vulkan --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      56. 60.100 / 56. 60.100
   libavcodec     58.112.101 / 58.112.101
   libavformat    58. 64.100 / 58. 64.100
   libavdevice    58. 11.102 / 58. 11.102
   libavfilter     7. 89.100 /  7. 89.100
   libswscale      5.  8.100 /  5.  8.100
   libswresample   3.  8.100 /  3.  8.100
   libpostproc    55.  8.100 / 55.  8.100
 Input #0, lavfi, from 'testsrc2=s=1920x1080':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 1920x1080
 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
 Input #1, lavfi, from 'color=gray:s=960x540':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #1:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 960x540
 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
 Stream mapping:
   Stream #0:0 (rawvideo) -> zmq
   Stream #1:0 (rawvideo) -> overlay:main
   format -> Stream #0:0 (rawvideo)
 Press [q] to stop, [?] for help
 Output #0, sdl,sdl2, to 'pipe:':
   Metadata:
     encoder         : Lavf58.64.100
     Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24(pc,
 progressive), 960x540 [SAR 1:1 DAR 16:9], q=2-31, 311040 kb/s, 25 fps, 25
 tbn, 25 tbc (default)
     Metadata:
       encoder         : Lavc58.112.101 rawvideo
 f

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Ticket URL: <https://trac.ffmpeg.org/ticket/8987>
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