[FFmpeg-user] Blur the Background with a Gradient

[Lou]

On Fri, 22 Aug 2014 17:42:01 +0800
Qianliang Zhang <zhangqianliang at gmail.com> wrote:

> Hi everyone,
> 
> I try blur video with 'boxblur' filter, and I find it helpful. But I want
> to blur my video with a gradient, any advice?

Make a gradient that is the same size as your input video:

$ convert -size 640x480 gradient: gradient.png

Then use ffmpeg (untested example):

$ ffmpeg -i video.mkv -loop 1 -i gradient.png -filter_complex \
  "[0:v]boxblur[blur]; \
   [blur][1:v]alphamerge[merged]; \
   [0:v][merged]overlay[out]" \
  -map "[out]" output.mkv