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Detect black screen and split with ffmpeg remux
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| # Splits video to separate scenes files when full black frames are found in the video | |
| # Inspired by https://gist.github.com/achesco/4dc2ebf13378a0a61fc26c7fe01f539e | |
| # Who got inspired by https://stackoverflow.com/a/38205105 | |
| #!/bin/bash | |
| file="" | |
| out="./" | |
| dur=0.05 | |
| stripaudio="" | |
| ratio=1.00 | |
| th=0.05 | |
| add=0.00 | |
| trim=0.00 | |
| usage () { | |
| echo "Usage: $(basename $0) [[[-o folder] [-d black duration]] | [-h]] -f file.mp4" | |
| echo | |
| echo "Options:" | |
| echo "-f, --file Input file" | |
| echo "-o, --out Outpup files folder path, default" | |
| echo " to current folder" | |
| echo "-d, --dur Duration for black detection in seconds. 0.05 default (practical single frame)" | |
| echo "-r, --ratio ffmpeg pic_th : Set the threshold for considering a picture black. 1.00 default" | |
| echo "-th, --threshold ffmpeg pix_th : Set the threshold for considering a pixel black. 0.00 default." | |
| echo "-t, --trim Substracts to splitting timestamp in seconds. 0 default" | |
| echo "-a, --add Adds to splitting timestamp in seconds. 0 default" | |
| echo "-sa, --strip-audio Strip audio" | |
| echo "-h, --help Display this help message" | |
| echo | |
| echo "Example: split.sh -d 0.5 -o /tmp/parts -f file.mp4" | |
| echo "Splits file.mp4 file to scenes with black frames during more than 0.5 second" | |
| echo "and saves output parts to /tmp/parts folder" | |
| } | |
| if [ "$1" = "" ]; then | |
| usage | |
| fi | |
| while [ "$1" != "" ]; do | |
| case $1 in | |
| -f | --file ) | |
| shift | |
| file=$1 | |
| ;; | |
| -d | --dur ) | |
| shift | |
| dur=$1 | |
| ;; | |
| -r | --ratio ) | |
| shift | |
| ratio=$1 | |
| ;; | |
| -th | --threshold ) | |
| shift | |
| th=$1 | |
| ;; | |
| -o | --out ) | |
| shift | |
| out=$1 | |
| ;; | |
| -t | --trim ) | |
| shift | |
| trim=$1 | |
| ;; | |
| -a | --add ) | |
| shift | |
| add=$1 | |
| ;; | |
| -sa | --strip-audio ) | |
| stripaudio="-an" | |
| ;; | |
| -h | --help ) | |
| usage | |
| exit | |
| ;; | |
| * ) | |
| usage | |
| exit 1 | |
| esac | |
| shift | |
| done | |
| cut_part () { | |
| duration_flag="" | |
| if [[ "$3" != "" ]]; then | |
| duration_flag="-t" | |
| fi | |
| echo "cutting from $1 during $3" | |
| printf -v fileout "$out/%04d_%s" $2 $filename | |
| ffmpeg -y -loglevel error -hide_banner -i $file -ss $1 $stripaudio $duration_flag $3 $fileout < /dev/null | |
| } | |
| filename=`basename $file` | |
| mkdir -p $out | |
| timefrom=0 | |
| i=1 | |
| ffmpeg -i $file -vf blackdetect=d=$dur:pic_th=$ratio:pix_th=$th -f null - 2> ffout | |
| black_start=( $(grep blackdetect ffout | grep black_start:[0-9.]* -o | grep "[0-9]*(\.[0-9]*)?" -oE) ) | |
| black_duration=( $(grep blackdetect ffout | grep black_duration:[0-9.]* -o | grep "[0-9]*(\.[0-9]*)?" -oE) ) | |
| > timestamps | |
| for ii in "${!black_start[@]}"; do | |
| half=$(bc -l <<< "${black_duration[$ii]}/2") | |
| middletime=$(bc -l <<< "${black_start[$ii]} + $half") | |
| echo $middletime | LC_ALL=en_US.UTF-8 awk '{printf "%f", $0}' >> timestamps | |
| echo "" >> timestamps | |
| done | |
| while read -r timestamp; do | |
| duration=`bc -l <<< "$timestamp-$timefrom+$add-$trim" | LC_ALL=en_US.UTF-8 awk '{printf "%f", $0}'` | |
| cut_part $timefrom $i $duration | |
| timefrom=`bc -l <<< "$timestamp+$add-$trim" | LC_ALL=en_US.UTF-8 awk '{printf "%f", $0}'` | |
| i=`expr $i + 1` | |
| done < timestamps | |
| if [[ "$timefrom" != 0 ]]; then | |
| cut_part $timefrom $i | |
| fi |
Author
Any way we are getting a Windows Command line version?
Author
I can’t translate this bash script to a straight Windows version without learning about it first, but I used ffmpeg in Windows before, so that can give you a head start. The other thing I know is possible is to use WSL which allows to use bash as a sub system directly in Windows 10/11.
Thank you for doing this! I was getting some unexpected behavior until I realized that your script's default's are different from ffmpeg's defaults for the blackdetect filter. To match the defaults, you could set
dur=2.00
ratio=0.98
th=0.10
at the beginning of the script.
Author
Nice, thanks for the input!
nice script!
This worked great for me. In my instance, was splitting a transfer from a VHS videotape, so had to use the ffmpeg blackdetect defaults (see above).
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Ooh nice catch, thanks!