[FFmpeg-user] Filter for smoothening gradual luminance changes?

Markku Tavasti tavasti at tavasti.fi
Tue Apr 18 22:26:10 EEST 2017

On 18.04.2017 14:02, Markku Tavasti wrote:
> Maybe I try to create script which would get frames as pictures. And in
> addition, to darkest parts of the video, there is huge noise in picture,
> averaging maybe 4 frames migth give better results.

Made a script:


if [ $# -gt 0 ] ; then interval=$1 ; fi
echo "Using interval of $interval seconds"

mkdir -p raw
mkdir -p avg
mkdir -p frm
for f in FHD*; do
   len=$(ffprobe  -select_streams v -show_streams $f 2>/dev/null| grep 
'duration=' | sed 's/.*=//i;s/\..*//')
   echo $f $len $FRM
   while [ $pos -lt $len ]; do
     ffmpeg -ss $pos -i $f -frames:v 4 raw/frm$(printf "%05d" 
${FRM})_%d.png 2>/dev/null
     convert raw/frm$(printf "%05d" ${FRM})_*.png -average 
avg/frm$(printf "%05d" ${FRM}).png
     mv raw/frm$(printf "%05d" ${FRM})_1.png frm
     rm raw/frm$(printf "%05d" ${FRM})_*.png

echo deflickering avg
cd avg
timelapse-deflicker.pl 2>/dev/null
echo deflickering frm
cd ../frm
timelapse-deflicker.pl 2>/dev/null
cd ..
ffmpeg -r 25 -pattern_type glob -i 'avg/Deflickered/*.png'  -c:v libx264 
-pix_fmt yuv420p avg.mp4
ffmpeg -r 25 -pattern_type glob -i 'frm/Deflickered/*.png'  -c:v libx264 
-pix_fmt yuv420p normal.mp4


And results https://youtu.be/5u3t6hiaEPI

Looks like ok. Uses lot of time and disk, real filter to ffmpeg would be 
much faster, but I am not in such mass production / my release schedule 
is not tight, so this will be sufficient to me.


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