Opened 10 months ago

Last modified 10 months ago

#8124 new enhancement

color option for perspective filter

Reported by: mkoch Owned by:
Priority: wish Component: avfilter
Version: git-master Keywords: perspective
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no


Summary of the bug:
When the "perspective" filter is used with parameter "sense=1", the size of the video becomes smaller and the outer area if filled with the pixel values from the border of the input video. It would be nice to have an option for filling the outer area with a color.

This example shows the problem:

rem Make a chessboard video
c:\ffmpeg\ffmpeg -f lavfi -i color=black:s=vga -vf geq=g='255*mod(floor(X/40)+floor(Y/40),2)' -t 5 -y in.mp4

rem Apply the perspective filter
c:\ffmpeg\ffmpeg -i in.mp4 -lavfi "perspective=x0=150:y0=125:x1=500:y1=75:x2=100:y2=375:x3=480:y3=420:sense=1" -y out.mp4

A known workaround is to pad the input video with a 1-pixel wide border (with alpha=0), before applying the perspective filter.
This is useful if you have a video in which a flickering computer screen is visible, and you want to overlay another video over this computer screen.

Change History (1)

comment:1 Changed 10 months ago by cehoyos

  • Component changed from ffmpeg to avfilter
  • Keywords perspective added
  • Priority changed from minor to wish
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