smartblur¶
Watch on youtube.com“smartblur” blurs the input video without impacting the outlines. (It is a slightly confusing filter which acts as “sharpen” when giving a negative value to “strength” while it is named “blur”.)
xxx_radius: radius that specifies the variance of the gaussian filter used to blur the image.
xxx_strength: strength. a positive value will blur the image whereas a negative value will sharpen the image.
xxx_threshold: threshold used as a coefficient to determine whether a pixel should be blurred or not. A value of 0 will filter all the image, a positive value will filter flat areas and a negative value will filter edges.
#! /bin/sh
ifn="Grape_Vineyard.mp4"
ifnb="`basename \"${ifn}\" .mp4`"
pref="`basename $0 .sh`"
#
luma_radius=${luma_radius:-2.0}
luma_strength=${luma_strength:-0.5}
#
ffmpeg -y -i "${ifn}" -filter_complex "
[0:v]split[0v1][0v2];
[0v1]crop=900:500:30:580,setsar=1,
smartblur=lr=${luma_radius}:ls=${luma_strength}
,drawbox=c=blue[b];
[0v2][b]overlay=30:580[v]
" -map '[v]' -an "${pref}_${ifnb}.mp4"