ffmpeg-webm-backforth

#!/bin/bash

# ffmpeg-webm-backforth

# Bash script to create webms which go back and forth. No audio is included.
# ffmpeg is required.
# See https://github.com/WhatIsThisImNotGoodWithComputers/ffmpeg-webm-scripts for usage.

# Created by WhatIsThisImNotGoodWithComputers (ohgod AT whatisthisimnotgoodwithcomputers DOT com)

#vars
TEMP_FOLDER="ffmpeg-temp"
OUTPUT_FILE="output.webm"
FRAMERATE="4500K"
TEMP=`getopt --long -o "i:s:t:o:f:c:a:" "$@"`

#params
eval set -- "$TEMP"
while true ; do
    case "$1" in
        -i )
            INPUT_FILE=$2
            shift 2
        ;;
        -s )
            START_TIME=$2
            shift 2
        ;;
        -t )
            TO_TIME=$2
            shift 2
        ;;
        -o )
            OUTPUT_FILE=$2
            shift 2
        ;;
        -f )
            FRAMERATE=$2
            shift 2
        ;;
        -c )
			#process cropping values
			IFS=',' read -ra ARR <<< "$2"
			NEW_CROP="$((${ARR[2]} - ${ARR[0]})):$((${ARR[3]} - ${ARR[1]})):${ARR[0]}:${ARR[1]}"
		    
		    #add
			if [ -n "$CROPSCALE" ]; then
				CSTEMP="$CROPSCALE"',crop='$NEW_CROP
				CROPSCALE=$CSTEMP
			else
				CROPSCALE='-vf crop='$NEW_CROP
			fi
            shift 2
        ;;
        -a )
			if [ -n "$CROPSCALE" ]; then
				CSTEMP="$CROPSCALE"',scale='$2
				CROPSCALE=$CSTEMP
			else
				CROPSCALE='-vf scale='$2
			fi
            shift 2
        ;;
        *)
            break
        ;;
    esac 
done;

#work
if [[ -d $TEMP_FOLDER ]]; then
	echo -e "\033[01;41;35mERROR: there's a directory $TEMP_FOLDER here.\033[0m"
	#exit 0
else
	#create dir
	echo -e "\033[05;44;33mCreating temp dir: $TEMP_FOLDER ...\033[0m"
	mkdir $TEMP_FOLDER
	#create shots
	echo -e "\033[05;44;33mUsing ffmpeg to create snapshots...\033[0m"
	ffmpeg -i "${INPUT_FILE}" -ss $START_TIME -to $TO_TIME -an -qscale 1 $TEMP_FOLDER/%06d.jpg
	#create webm
	echo -e "\033[05;44;33mUsing ffmpeg to encode snapshots into BACK FORTH webm\033[0m"
	cat $(ls $TEMP_FOLDER/*jpg && ls -r $TEMP_FOLDER/*jpg) | ffmpeg -f image2pipe -vcodec mjpeg -r 25 -i - -c:v libvpx -crf 20 -b:v $FRAMERATE $CROPSCALE -threads 0 -an $OUTPUT_FILE
	#cleaning up
	echo -e "\033[05;44;33mCleaning up...\033[0m"
	rm -r $TEMP_FOLDER
	#Uncomment following line if you're having trouble with cropping and or scaling
	#echo $CROPSCALE
fi

exit 0