#!/usr/bin/env bash
# Script to generate WebM video for 4Chan using ffmpeg

author="bp"
title="Encoded for 4Chan"
resolution="-1"
slices=4
lag=16
cpu=2
mbLimit=3
timeLimit=45
beginTime="00:00:00"
outFile="out.webm"

usage()
{
cat << EOF
usage: $0 options
This script will create WebM videos for 4Chan requirements.
OPTIONS:
	-h Show this message
	-i Input media file (required)
	-o Output media file (defaults to out.webm)
	-r Output Resolution (240 for 240p, 720 for 720p, etc... Defaults to -1 (original))
	-m Target output size in megabytes (default is 3)
	-b Begin time (ex: 00:32.65.342, defaults to 0)
	-e Time length of video (in seconds, defaults to 45)
	-s Slices (1-3 lowdef, 5-8 highdef, defaults 4)
	-l Lag in frames (frames to read ahead, 16 default, max 25)
	-c Total cpu's to use (default is 2)
	-u Specify alternate subtitle file (defaults to source filename but with a .ass extension)
	-f Optional ffmpeg filters you would like apply ex: "crop=100:200:10:20, edgedetect"
	-p Optional ffmpeg paramaters you would like to apply ex: "-loglevel quiet"
	-x Speedplay end time - speedup source video to fit within time frame
	   (truncate 1 hr into 2 mins, etc. Must use end time of source as parameter ex: 01:23:17)
	-a Author ex: "John Doe"
	-t Title ex: "My Title"
	-v View 4ChanWebM history (show previous commands used)
	For any parameter which is more than one word, use quotes to surround it.
EOF
}

getBeginTimeSecs()
{
	read hours mins secs <<<$(IFS=":"; echo $beginTime)

	hours=$(($hours*60*60))
	mins=$(($mins*60))
	beginTimeSecs=$(($hours+$mins+$secs))

	if [[ $beginTimeSecs -gt 9 ]];
	then
		beginTimeSecs=$(($beginTimeSecs-5))
		beginTimeSecsSlow=5
	else
		beginTimeSecsSlow=$beginTimeSecs
		beginTimeSecs=0
	fi

	echo Begin Time: $(($beginTimeSecs+5))
}

getEndSpeedplaySecs()
{
	read spHours spMins spSecs <<<$(IFS=":"; echo $spEndTime)

	spHours=$(($spHours*60*60))
	spMins=$(($spMins*60))
	spEndTimeSecs=$(($spHours+$spMins+$spSecs))

	echo Speed End Time: $spEndTime
	echo End Time Secs: $spEndTimeSecs
}

speedPlay()
{
	getBeginTimeSecs
	getEndSpeedplaySecs

	speedLength=$(($spEndTimeSecs-$beginTimeSecs-5))
	pts=`echo $speedLength*60/$timeLimit|bc -l`

	speedplay=", setpts=(60/$pts)*PTS"
	filters=$filters$speedplay
}

while getopts "hi:o:r:m:b:e:s:l:c:u:f:p:x:a:t:v" OPTION; do
	case $OPTION in
		h)
			usage
			exit 1
			;;
		i)
			inFile=$OPTARG
			;;
		o)
			outFile=$OPTARG
			;;
		r)
			resolution=$OPTARG
			;;
		m)
			mbLimit=$OPTARG
			;;
		b)
			beginTime=$OPTARG
			;;
		e)
			timeLimit=$OPTARG
			;;
		s)
			slices=$OPTARG
			;;
		l)
			lag=$OPTARG
			;;
		c)
			cpu=$OPTARG
			;;
		u)
			subtitle=$OPTARG
			;;
		f)
			filters=", "$OPTARG
			;;
		p)
			params=" "$OPTARG
			;;
		x)
			spEndTime=$OPTARG
			;;
		a)
			author=$OPTARG
			;;
		t)
			title=$OPTARG
			;;
		v)
			cat ~/.4ChanWebMHistory
			exit 1
			;;
		?)
			usage
			exit
			;;
	esac
done

getBeginTimeSecs

if [[ ! -z $spEndTime ]];
then
	speedPlay
fi

if [[ -z $inFile ]] || [[ ! -r $inFile ]];
then
	echo You must specify a readable media file to convert. Ex: -i movie.mkv
	exit 2
fi

path="${inFile%/*}"
if [[ $path == $inFile ]];
then
	path="";
else
	path=$path"/"
fi

filename=$(basename "$inFile")
extension="${filename##*.}"
filename="${filename%.*}"

if [[ -z $subtitle ]];
then
	subtitle="$path$filename.ass"
fi

bitrate=$(($mbLimit*8192/$timeLimit))"K"
history="4ChanWebM -i \"$inFile\" -o \"$outFile\" -r $resolution -m $mbLimit -b $beginTime -e $timeLimit -s $slices -l $lag -c $cpu -u $subtitle -a \"$author\" -t \"$title\""
echo $history>>~/.4ChanWebMHistory

if [ -r "$subtitle" ];
then
	ffmpeg -ss $beginTimeSecs -i "$inFile" -vf "scale=-1:$resolution, ass=$subtitle$filters" -ss $beginTimeSecsSlow -t $timeLimit$params -an -c:v libvpx -b:v $bitrate -quality best -slices $slices -auto-alt-ref 1 -lag-in-frames $lag -threads $cpu -pass 1 -f webm /dev/null -y
	ffmpeg -ss $beginTimeSecs -i "$inFile" -vf "scale=-1:$resolution, ass=$subtitle$filters" -ss $beginTimeSecsSlow -t $timeLimit$params -an -c:v libvpx -b:v $bitrate -quality best -slices $slices -auto-alt-ref 1 -lag-in-frames $lag -threads $cpu -pass 2 -metadata title="($author) $title" "$outFile" -y
else
	ffmpeg -ss $beginTimeSecs -i "$inFile" -vf "scale=-1:$resolution$filters" -ss $beginTimeSecsSlow -t $timeLimit$params -an -c:v libvpx -b:v $bitrate -quality best -slices $slices -auto-alt-ref 1 -lag-in-frames $lag -threads $cpu -pass 1 -f webm /dev/null -y
	ffmpeg -ss $beginTimeSecs -i "$inFile" -vf "scale=-1:$resolution$filters" -ss $beginTimeSecsSlow -t $timeLimit$params -an -c:v libvpx -b:v $bitrate -quality best -slices $slices -auto-alt-ref 1 -lag-in-frames $lag -threads $cpu -pass 2 -metadata title="($author) $title" "$outFile" -y
fi

if [[ -r "ffmpeg2pass-0.log" ]];
then
	rm ffmpeg2pass-0.log
fi