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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

  


  

  


• FFMPEG : Black background after scaled and cropped

  30 septembre 2015, par kenicky

  I am using scale and crop for creating a new video. The problem is the nullsrc’s size is greater than the input, leaving a blinking green background. How can I change the blinking green background to black ?

  here is my code :

  ffmpeg -y -i 1.mov -filter_complex "nullsrc=size=640x480 [base]; [0:v] setpts=PTS-STARTPTS, scale=320x480 [left]; [base][left] overlay=shortest=0:x=160" -c:v libx264 -t 5 output.mp4

• Make green nullsrc to black

  2 octobre 2016, par Ultgin

  I have a video which hasn’t 1920x1080 so I need to make it.

  I try to use next command :

  ffmpeg -i "video.avi" -filter_complex "nullsrc=size=1920x1080 [0:v]; [0:v] overlay=shortest=1:x=200:y=100" -r 30 -c:v libx264 -preset fast -crf 18 -profile:v high -bf 2 -flags +cgop -coder 1 -pix_fmt yuv420p -strict -2 -c:a aac -b:a 384k "video.mp4"

  But I got a green frame over the video like this - http://i.imgur.com/QNVUGb5.jpg

  I dont find a solution to make a green in any other color.

  How possible to make green frame to black frame ?

  Thanks.