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• FFmpeg screen blend mode turns image pink

  18 mai 2021, par IAmDamoSuzuki

  I'm having trouble using the screen blend mode. I'm trying to create a video delay/echo effects. I have things working fairly well, but whenever I try to use the screen blend mode I get a pink image. Other blend modes don't have this issue, but the screen mode is likely going to give me the best visual results.

  


  I see that someone else asked a similar question here, and the answers suggested converting to RGBa before doing the blends. I've tried this and it didn't work. Here's my code and ffmpeg info.

  


  ffmpeg -i sampleVideo.mov -c:v prores -profile:v 3 -filter_complex "split[dry][toEcho];[toEcho]setpts=PTS+0.2/TB[wet];[wet][dry]blend=all_mode=screen:all_opacity=1,format=yuv422p10le[out]" -map [out] sampleVideo_echo.mov


  


  ffmpeg info :

  


  ffmpeg version 4.2.3 Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.17)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.3_1 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags=-fno-stack-check --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/morgan/Movies/AVAA/TapeDamage01.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:00:05.16, start: 0.000000, bitrate: 3717 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 81:80 DAR 27:20], 3560 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
    Metadata:
      handler_name    : Apple Video Media Handler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 160 kb/s (default)
    Metadata:
      handler_name    : Apple Sound Media Handler
File '/Users/morgan/Movies/AVAA/TapeDamage01_echo.mov' already exists. Overwrite ? [y/N] y
Stream mapping:
  Stream #0:0 (h264) -> split
  format -> Stream #0:0 (prores)
Press [q] to stop, [?] for help
Output #0, mov, to '/Users/morgan/Movies/AVAA/TapeDamage01_echo.mov':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
    Stream #0:0: Video: prores (HQ) (apch / 0x68637061), yuv422p10le, 640x480 [SAR 81:80 DAR 27:20], q=2-31, 200 kb/s, 29.97 fps, 30k tbn, 29.97 tbc (default)
    Metadata:
      encoder         : Lavc58.54.100 prores


  


  Here's a sample of the input file :

  


  

  


  and here's the pink output

  


  

  


• capture.isOpened() returns false in python [closed]

  24 décembre 2019, par Elnaz Yousefi

  I tried to read a video (.avi file) by cv2.VideoCapture in Python, but capture.isOpened() returns false.
  when I execute python in cmd, it returns "Python 3.7.2". Also, when I use "pip install opencv-python" in command line, OpenCV was successfully installed.
  By the way, I noticed that the version of opencv which is installed is 4.1.2 and the ffmpeg file is named "opencv_videoio_ffmpeg412".
  Is everything right ? so what’s the problem ?

• cvCaptureFromFile always returns NULL, Visual Studio 2005

  14 septembre 2012, par user1671173

  I've got a problem with the cvCaptureFromFile function. It always returns NULL. I've done some research on the internet and I've added PATH to ffmpeg's "bin" directory.
  But it's still the same. So I've tried to open the desired file with ffplay.exe. It returns an error which says "Invalid data found when processing an input". It is a "mjpg" file, which should be played with ffmpeg. Then I tried the same with some "mpg" file.
  Now the message is "no such file or directory" which is not true, because the file is in the place. What else should I do ?
  The files all right with Media-Player and VLC player.
  Please help !