Prepare Video for Byte/IG Story/etc

prepareVideoForSocialMedia.sh

#!/bin/bash

#Quick and dirty way to get a video ready for byte or instagram or other
#These are usually in a ratio of 9:16, as opposed to usual viewing of 16:9
#Requires: ffprobe, ffmpeg

#Example usages:
# 1)
#   	sh prepareVideoForSocialMedia.sh someStream.mp4 00:01:45 6 510
# 2)
#   	sh prepareVideoForSocialMedia.sh someStream.mp4 02:17:00 6

#This is just a helper function for ease of use
function convert_seconds_to_hms () {
    num=$1
    min=0
    hour=0
    sec=0
    if((num>59));then
        ((sec=num%60))
        ((num=num/60))
        if((num>59));then
            ((min=num%60))
            ((num=num/60))
            ((hour=num))
        else
            ((min=num))
        fi
    else
        ((sec=num))
    fi

    #pad zeroes
    if [[ $hour -lt 10 ]]
	    then
	    	hour="0$hour"
	fi
    if [[ $min -lt 10 ]]
	    then
	    	min="0$min"
	fi
    if [[ $sec -lt 10 ]]
	    then
	    	sec="0$sec"
	fi
    echo "$hour:$min:$sec"
}

ORIG=$1 #the file you want to extract from
START_TIME=$2 #where you want the start. In the format HH:mm:ss
LENGTH=$3 #how many seconds it should be (byte is 6, instagram is 30. I think)
X_CROP=$4 #the x coordinate you want at the centre of the video (i.e. what you want viewers to see)
# If X_CROP is left blank, the video will simply get rotated and scaled to fit
LENGTH="$(convert_seconds_to_hms 5)"
echo $LENGTH

if [ -z $X_CROP]
	then
		#Extract segment, rotate, and scale
		echo "No X-Coordinate provided, rotating and scaling instead of cropping"
		ffmpeg -i $ORIG -ss $START_TIME -t $LENGTH -filter:v "transpose=0, scale=-1:1080"  -c:a copy ${ORIG%.*}-prepared.mp4 
	else
		#Extract segment, crop, and scale
		DIMS=`ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=s=x:p=0 $ORIG`
		x=${DIMS%x*}
		y=${DIMS##*x}
		width=`echo "scale=5;$y / (16 / 9)" | bc`
		width=`echo $width|cut -f1 -d"."`
		height=$y

		echo $width
		echo $height

		#This does sort of assume your source video uses a happy audio codec
		ffmpeg -i $ORIG -ss $START_TIME -t $LENGTH -filter:v "crop=$width:$height:$X_CROP:0, scale=-1:1080"  -c:a copy ${ORIG%.*}-prepared.mp4
fi


#Explanation of what this script does:
#
#	This script takes a slice of your video, denoted by *
#	Making it nice for viewing on mobile
#  | _ _ _ _ _ _ _ _ _ *** _ _ _ _ _ |
#  |                   ***           |
#  |                   ***           |
#  |                   ***           |
#  |                   ***           |
#  |                   ***           |
#  |                   ***           |
#  |                   ***           |
#  | _ _ _ _ _ _ _ _ _ *** _ _ _ _ _ |
#
# Of course, you can just use the rotate option if you want