Bash script to dowload a video section by timestamp via youtube-dl and ffmpeg (works for youtube, twitch, etc.)

dlclip.sh

#!/bin/bash

function printUsage() {
        echo "usage: bash $0 -i <inurl> -ss <starttime> -t <duration> -o <outfile>"
        echo '   other args are passed directly to youtube-dl; eg, -r 40K'
}

if [ "$#" -eq 0 ]; then
    printUsage
    exit
fi

# fetch command-line arguments
starttime=
duration=
inurl=
otherargs=
outfile=
copy="-c copy"

while [ $# -gt 0 ]; do
    # echo "debug arg $1 $2"
    if [ "$1" == "-h" ] || [ "$1" == "--h" ]; then
        echo "Downloads a portion of a youtube video or twitch VOD"
        printUsage
        exit
    elif [[ $1 == "-i" ]]; then
        inurl="$2"
        shift
        shift
    elif [[ $1 == "-ss" ]]; then
        starttime="-ss $2"
        shift
        shift
    elif [[ $1 == "-t" ]]; then
        duration="-t $2"
        shift
        shift
    elif [[ $1 == "-o" ]]; then
        outfile="$2"
        shift
        shift
    elif [[ $1 == "--reencode" ]]; then
        copy=""
        shift
    else
        otherargs+="$1"
        shift
    fi
done

# mandatory arg check
if [[ -z "${inurl// }" ]]; then
    echo "Error: missing inurl"
    printUsage
elif [[ -z "${outfile// }" ]]; then
    echo "Error: missing outfile"
    printUsage
fi

printf "Saving to: %s ...\n" "$outfile"

ydlcmd="youtube-dl -g $inurl $otherargs"
echo "=> $ydlcmd"
streamurl=$(eval $ydlcmd)
echo "<= $streamurl"

if [[ -z "${outfile// }" ]]; then
    outfile="$(youtube-dl --get-outfile -f best $otherargs "$inurl")"
fi

tmp=IFS
IFS=" "
inputstr=""

sources=($(echo "$streamurl" | tr '\n' ' '))
for source in "${sources[@]}"
do
   inputstr+=" -i \"$source\" "
done

cmd="ffmpeg -loglevel warning -hide_banner -stats $starttime $inputstr $copy $duration \"$outfile\""
echo "=> $cmd"
eval $cmd