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• FFmpeg : Removing black outline on overlay after alphamerge

  9 novembre 2023, par trmd

  Similar question : FFmpeg transparent PNG black outline issue

  


  When using FFmpeg to create a GIF from an mp4, masking the video using alphamerge and a PNG-mask, and overlaying a circle outline, black lines occur on both the video and the circle in the final GIF.

  


  From this question, some suggestions are made to add alpha=premultiplied and format=rgb,format=yuv420p in the overlay-filter. This removes the black line (on the circle), but the masking from alphamerge no longer works.

  


  Filter used which generates black outlines :

  


  [0][1]alphamerge[merged];
[merged][2:v]overlay=
    format=auto:
    alpha=premultiplied[withCircleOverlay];
[withCircleOverlay]scale=${size}x${size}[scaled];
[scaled]split[s0][s1];
[s0]palettegen=reserve_transparent=on:transparency_color=ffffff[p];
[s1][p]paletteuse


  


  Filter used which removes outlines, but also cropping :

  


  [0][1]alphamerge[merged];
[merged][2:v]overlay=
    alpha=premultiplied:
    format=rgb,format=yuv420p[withCircleOverlay];
[withCircleOverlay]scale=${size}x${size}[scaled];
[scaled]split[s0][s1];
[s0]palettegen=reserve_transparent=on:transparency_color=ffffff[p];
[s1][p]paletteuse


  


  Command used :

  


  ffmpeg -i movie.mp4 -i mask.png -i circle.png -filter_complex <filter> output.gif&#xA;</filter>

  


  What I've tried :

  


  

  • Changing the format-parameter on overlay to a lot of different values.

  


  • Changing the order of the filters.

  


  • Playing around with running multiple ffmpeg-passes : First doing the merging, saving this to a file, and then adding the circle afterwards. I think this in principle should work if I tinker with it enough.

  


  


  Are there any ways to get around this issue ?

  


  Image with black outlines

  


  

  


  Image without outline, but also without alphamerge cropping

  


  

  


• how can fix a video which has a smaller width and black sides when a pad is added with ffmpeg

  24 mai 2019, par eliud nyamai

  im aplying a pad to a video but the video is displaying with black sides after i add a pad with ffmpeg instead of being full screen.can somebody help me correct it or give me an alternative of using a pad

  it is on an ubuntu server

  ffmpeg -i IMG_9079.mov -ss 00:00:20.0 -vcodec libx264 -vf "pad=width=1280:height=1280:x=0:y=280:color=white" -acodec copy -t 20 output_withpad.mov

  I expect the video to be full screen with a pad at the bottom

• 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.