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• Change White to Black in a GIF or crop GIF into a circle with Python

  28 juin 2022, par tcleckner

  I have a GIF that I am trying to change all the white pixels to black. Not sure where to start.

  


  Alternatively the GIF could be cropped to just the circle graphic on the left side of the GIF. I have used ffmpeg-python to crop the GIF down to a square around the circle but have yet to be able to crop it to a circle.
ffmpeg.crop(stream, 46,117,390,390)
Any insight is appreciated.

  


• 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 : 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