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• FFMPEG - CONVERT VIDEO TO GREYSCALE EXCEPT ONE COLOR ? LEAVE ONE COLOR, THE REST BLACK & WHITE ? [closed]

  19 décembre 2023, par scm360

  I have been researching and cannot find anything on how to preserve just one color / color range ; while converting a video to greyscale / black & white using FFMPEG. For example ; all black and white, except the peoples Blue Jeans, etc.

  


  Anyone know how to do this in FFMPEG ?

  


  Thanks in advance.

  


  I haven't actually found anything that has promise to achieve this. Of course I know how to convert everything to greyscale / black & white. But, not just leave the color / color range.

  


• Center crop image overlay using FFmpeg

  27 mai 2020, par HB.

  I currently have an image that is being overlayed on top of a video, as demonstrated in this image :

  



  

  



  The blue square is representing the video and the purple lines are representing the image on top of the video.

  



  ---

  



  Currently, I have the following command :

  



  "-i", InputVideoPath, "-i", InputImagePath, "-filter_complex", "[0:v]scale=iw*sar:ih,setsar=1,pad='max(iw\\,2*trunc(ih*9/16/2))':'max(ih\\,2*trunc(ow*16/9/2))':(ow-iw)/2:(oh-ih)/2[v0];[1:v][v0]scale2ref[v1][v0];[v0][v1]overlay=x=(W-w)/2:y=(H-h)/2[v]", "-map", "[v]", "-map", "0:a", "-c:v", "libx264", "-preset", "ultrafast", "-r", "30", OutputPath


  



  This adds black padding to the sides of the video and outputs the following :

  



  

  



  But I would like the center crop the image that is being overlayed instead, giving me this output :

  



  

  



  I've seen answers that demonstrate how to crop an image or crop 2 videos, but I couldn't find a way to center crop an image that is being overlayed on top of a video.

  



  The video I'm testing with is 1920x1080 and the size of the image is not constant.

  



  Any help in achieving this will be appreciated.

  



  ---

  



  EDIT (This edit is to add more clarification).

  



  Please have a look at the image below :

  



  

  



  The image above demonstrates :

  



  

  • Purple Lines : The entire screen of the device/player, this will be used as the input image. The user draws on the screen/player.

  


  • Blue : The input video, scaled to fill the screen

  


  • Green : The actual size of the input video

  


  



  With this example, the player/image is 1920x1080 and the actual video size is 640x640. So the video is scaled 440x440 to fill the player.

  



  ---

  



  I tried to use a simple overlay, with the hopes that it will crop the video/image and output a video with the image at the same position as what was displayed on the device, by doing the following :

  



  ffmpeg -i InputVideo -i InputImage -filter_complex "overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2" -c:v libx264 -preset ultrafast OutputPath


  



  But, the image is not at the same position as what it was on the device.

  



  I suspect that I will have to take into account the size difference between the scaling of the video to fit into the video player.

  



  I'm not sure how I can do this ?

  


• doxy : Fix link in badge color

  16 décembre 2013, par Luca Barbato

  doxy : Fix link in badge color
  Green on blue was not exactly optimal.
  Signed-off-by : Luca Barbato <lu_zero@gentoo.org>
  

  • [DH] doc/doxy/doxy_stylesheet.css