loop_videos

#!/bin/bash

usage () {
    echo "usage: loop_videos [file] [totalsecs]"
    echo "       The file contains the video(s) you want to loop, each on a seperate line."
    echo "       The totalsecs is the length, in seconds, you want to output video(s) to be."
    echo "       Note: total length of output video may be longer than specififed, but it will never be shorter."
}

##Error Check##
    error=0

    #correct number of arguments
    if [ $# != 2 ]; then
      usage
      exit
    fi

    #check if file exists
    if [ ! -f $1 ]; then
        echo "File does not exist."
        error=1
    fi

    #check is totalsecs is a valid number
    if ! [[ $2 =~ ^[1-9][0-9]*$ ]]; then
        echo "Totalsecs is not a valid number."
        error=1
    fi

    #if there was an error, exit
    if [ $error == 1 ]; then
        usage
        exit
    fi


files=$1
totalsecs=$2
tmpfile=".tmplooptmp.txt"
outputlocation=~/Desktop/looped_videos

#read through specified file [line by line]
j=1
mkdir -p $outputlocation
while read file; do

    #stackoverflow.com/questions/965053/extract-filename-and-extension-in-bash
    filename=$(basename "$file")
    extension="${filename##*.}"
    filename="${filename%.*}"

    ##Error Check##
        #check to see if file exists
        if [ ! -f $file ]; then
            echo "$file does not exist."
            continue
        fi

        #check to see if extension is supported
        count=`ffmpeg -formats 2> /dev/null | grep -s -c $extension`
        if [ $count == 0 ]; then
            echo "$file is not a supported by ffmpeg."
            continue
        fi

    #get the length of the video in milliseconds
    millisec=$(mediainfo --Inform="General;%Duration%" $file)
    #calculate the number of loops needed
    sec=$(($millisec / 1000))
    numloops=`python -c "from math import *; print(int(ceil(float($totalsecs)/float($sec))))"`

    #create a file that lets ffmpeg know how many times it needs to loop
    echo -n > $tmpfile
    for((i = 0; i < $numloops; i++)); do
        echo "file '$file'" >> $tmpfile
    done

    echo "Video concatation started for video $j"
    ffmpeg -nostdin -f concat -i $tmpfile -c copy $outputlocation/$filename.loop.$extension 2> /dev/null

    j=$(($j + 1))

done < $files
rm -f $tmpfile