webm.bash

#!/bin/bash
# webm.bash
# Requires: ffmpeg, mplayer, gawk

set -o errexit
shopt -s nocaseglob
shopt -s nocasematch

# Default temporary font dir, rescursively deleted at the end
FONTDIR="$HOME/.fonts/tmp/"
# Log file ffmpeg uses by default
LOG="ffmpeg2pass-0.log"
# Default codec
CODEC="libvpx"
# Default width of output
W="-1"
# Default height of output
H="-1"
# Default CRF
CRF="4"
# Default output limit in megabytes
MBLIMIT="3"
# Default number of threads that ffmpeg will use
THREADS="$(nproc)"
# Default lag in frames
LAG="16"
# Default slices
SLICES="8"

# Default X display for screen recorder
XDISP=":0"
# Default screen recorder FPS
FPS="60"
# Default follow distance for screen recorder when using -follow_mouse
DIS="75"

# Slave input config file, delete ~/.mplayer/webmcrop if you make changes
MPCONFIG="$(cat <<EOF
z   pausing_keep get_time_pos
w   pausing_keep change_rectangle 3 -10
a   pausing_keep change_rectangle 2 -10
s   pausing_keep change_rectangle 3 10
d   pausing_keep change_rectangle 2 10
KP8 pausing_keep change_rectangle 1 -10
KP4 pausing_keep change_rectangle 0 -10
KP2 pausing_keep change_rectangle 1 10
KP6 pausing_keep change_rectangle 0 10
EOF
)"

Usage()
{
cat <<EOF

webm.bash

It just werks.

Usage:
	-i Input file, e.g. inputfilename.mkv (required)

	-o Output file, e.g. output.webm
		Defaults to inputfilename_HH:MM:SS.MS_HH:MM:SS.MS.webm if you
		specify a starting time and ending time, otherwise defaults to
		inputfilename.webm.

	-s Starting time in HH:MM:SS.MS, e.g. 02:23:59.00
		Defaults to starting time of input file.

	-e Ending time in HH:MM:SS.MS, e.g. 02:24:01.30
		Defaults to ending time of input file.

	-q CRF, e.g. 10
		Enables constant quality mode and sets quality: values 0-63
		with lower values being lower quality.
		Defaults to $CRF

	-b Output bitrate in kbps, e.g. 1000

	-y Segmented MKV mode
		When using a video player that plays back ordered chapters or
		segmented MKVs (mpv) to manually get the starting and ending
		times, use this mode to correct times for ffmpeg automatically.

	-c Crop output using mplayer (interactive)
		Launches mplayer to crop with your w, a, s and d keys to move
		the rectangle and your keypad arrow keys to adjust the size of
		the rectangle filter.

	-u Burn subtitles into output (interactive)
		Prompts you to select the stream containing the subtitles you
		wish to hardsub into the output video.

	-v Cut output video times using mplayer (interactive)
		Launches mplayer so you can select your start and end times
		using the z key. Only the first and the last inputs will be
		taken into account.

	-w Output width, e.g. 640
		When overriding either the default width or height, the output
		will be scaled to the correct aspect ratio, but not when you
		override both.
		Defaults to $W

	-h Output height, e.g. 480
		Defaults to $H

	-m Filesize limit in megabytes, e.g. 4
		Defaults to $MBLIMIT

	-t Threads, e.g. 8
		Number of threads to use for encoding, try setting this option
		to 1 if the file gets cut off (i.e. slightly over the size
		limit.)
		Defaults to $THREADS

	-l Lag in frames, e.g. 25
		Number of frames for ffmpeg to look ahead for when encoding.
		Defaults to $LAG

	-x Slices, e.g. 4
		Directs the encoder to split the coefficient encoding across
		multiple data partitions that can be encoded independently.
		A value of 1 or 2 is recommended for small images, and 4 or
		8 is recommended for high definition images.
		Defaults to $SLICES

	-f Additional ffmpeg filters, e.g. "crop=1140:574:450:100,"

	-p Additional ffmpeg parameters, e.g. "-loglevel quiet"

	-r Record screen with ffmpeg (interactive)

	-d Screen recorder window cropping (interactive)

	-z Follow the mouse when recording the screen
		Requires width and/or height parameter to be passed.

	-9 Use the vp9 codec instead of vp8

EOF
}

while getopts "cuvyrdz9i:o:s:e:b:w:h:q:m:t:l:x:f:p:" OPTION; do
	case "$OPTION" in
		c)  CROP=true;;
		u)  SUB=true;;
		v)  CUT=true;;
		y)  SEGMENTED=true;;
		r)  XRECORD=true;;
		d)  XCROP=true;;
		z)  XMOUSE=true;;
		9)  CODEC="libvpx-vp9";;
		i)  IF="$OPTARG";;
		o)  OF="$OPTARG";;
		s)  ST="$OPTARG";;
		e)  ET="$OPTARG";;
		b)  BR="$OPTARG";;
		w)  W="$OPTARG";;
		h)  H="$OPTARG";;
		q)  CRF="$OPTARG"
		    CQ=true;;
		m)  MBLIMIT="$OPTARG";;
		t)  THREADS="$OPTARG";;
		l)  LAG="$OPTARG";;
		x)  SLICES="$OPTARG";;
		f)  ADDFILTERS="$OPTARG";;
		p)  ADDPARAMS="$OPTARG";;
		?)  Usage
		    exit 1;;
		:)  Usage
		    exit 1;;
	esac
done

ScreenRecorder()
{
	IF="$(date +'%Y-%m-%d %k:%M:%S').mkv"

	# Current display resolution
	RES="$(xrandr -q | awk -F 'current' -F ',' 'NR==1 {gsub("( |current)",""); print $2}')"

	if [[ "$XMOUSE" = true ]] ; then
		if [[ "$W" -eq "-1" && "$H" -eq "-1" ]] ; then
			echo "Specify a width and/or height" && exit 1
			exit 1
		elif [[ "$W" -eq "-1" ]] ; then
			W="$H"
		elif [[ "$H" -eq "-1" ]] ; then
			H="$W"
		fi

		RES="${W}x${H}"

		ffmpeg -f x11grab -follow_mouse "$DIS" -s "$RES" -i "$XDISP" -r "$FPS" \
			-threads "$THREADS" -crf 0 -preset ultrafast -c:v libx264 "$IF"

	elif [[ $XCROP = true ]] ; then
		echo "Click on the window you wish to record..."

		XINFO="$(xwininfo)"
		WINX="$(echo "$XINFO" | grep "Absolute upper-left X" | awk '{print $4}')"
		WINY="$(echo "$XINFO" | grep "Absolute upper-left Y" | awk '{print $4}')"
		WINW="$(echo "$XINFO" | grep Width | awk '{print $2}')"
		WINH="$(echo "$XINFO" | grep Height | awk '{print $2}')"

		XCROPS="crop=${WINW}:${WINH}:${WINX}:${WINY}"

		ffmpeg -f x11grab -s "$RES" -i "$XDISP" -r "$FPS" -vf "$XCROPS" \
			-threads "$THREADS" -crf 0 -preset ultrafast -c:v libx264 "$IF"
	else
		ffmpeg -f x11grab -s "$RES" -i "$XDISP" -r "$FPS" -threads "$THREADS" \
			-threads "$THREADS" -crf 0 -preset ultrafast -c:v libx264 "$IF"
	fi
}

SlaveInput()
{
	# Check if ~/.mplayer/webmcrop exists, otherwise create it
	if  [[ ! -f "$HOME/.mplayer/webmcrop" ]] ; then
		echo "$MPCONFIG" > "$HOME/.mplayer/webmcrop"
	fi

	if [[ -z "$STS" ]] ; then
		# ffmpeg with the rectangle filter, use webmcrop as input conf
		mplayer -title "Cut Video" -fixed-vo -idle -vf rectangle \
			-osdlevel 3 -osd-fractions 2 -input conf=webmcrop "$IF" 2>&1
	else
		mplayer -title "Crop Video" -ss "$STS" -fixed-vo -idle -vf rectangle \
			-osdlevel 3 -osd-fractions 2 -input conf=webmcrop "$IF" 2>&1
	fi
}

SecondsToTimestamp()
{
	# SS.MS to HH:MM:SS.MS, ANS_TIME_POSITION only returns MS to one digit
	awk -F . '{printf("%02d:%02d:%02d.%1d",($1/60/60%24),($1/60%60),($1%60),($2))}'
}

CutVideo()
{
	STARTEND="$(SlaveInput | grep ANS_TIME_POSITION)"

	# First and last occurance of ANS_TIME_POSITION in $STARTEND
	STS="$(echo "$STARTEND" | head -1 | awk -F = '{print $2}')"
	ETS="$(echo "$STARTEND" | tail -1 | awk -F = '{print $2}')"
	ST="$(echo "$STS" | SecondsToTimestamp)"
	ET="$(echo "$ETS" | SecondsToTimestamp)"
}

SetOutputFilename()
{
	if [[ -z "$ST" || -z "$ET" ]] ; then
		# Output filename when converting the complete input file
		OF="$(echo "${IF%.*}" | awk -F / '{print $NF}').webm"
	else
		OF="$(echo "${IF%.*}" | awk -F / '{print $NF}')_${ST}_${ET}.webm"
	fi
}

CalculateRunningTime()
{
	# Get start (not sure if this matters) and end time from ffmpeg
	if [[ -z "$ST" ]] ; then
		ST="$(ffmpeg -i "$IF" 2>&1 | grep Duration | awk '{print $4}' | tr -d ,)"
	fi
	if [[ -z "$ET" ]] ; then
		ET="$(ffmpeg -i "$IF" 2>&1 | grep Duration | awk '{print $2}' | tr -d ,)"
	fi

	if [[ -z "$STARTEND" ]] ; then
		# Convert HH:MM:SS.MS to simple seconds with awk, if not already set
		ETS="$(echo "$ET" | awk -F : '{print ($1*3600) + ($2*60) + $3}')"
		STS="$(echo "$ST" | awk -F : '{print ($1*3600) + ($2*60) + $3}')"
	fi

	if [[ "$SEGMENTED" = true ]] ; then
		OP="$(ffmpeg -i "$IF" 2>&1 | grep 'Chapter #0.0' | awk '{print $6}')"
		STS="$(bc <<< "$STS - $OP")"
		ETS="$(bc <<< "$ETS - $OP")"
	fi

	# Running time of output selection
	TIME="$(bc <<< "$ETS - $STS")"
}

CalculateBitrate()
{
	if [[ "$(bc <<< "$TIME < 10")" -eq 1 && -z "$BR" ]] || [[ "$CQ" = true ]] ; then
		# If running time less than 10 and no bitrate specified or CQ mode
		BITRATE="-crf $CRF -qmax $(bc <<< "$CRF + 6")"
	elif [[ -z "$BR" ]] ; then
		# Calculates bitrate depending on $MBLIMIT
		BITRATE="-b:v $(bc <<< "($MBLIMIT * 8192) / $TIME")K"
	else
		BITRATE="-b:v ${BR}K"
	fi
}

CropOutput()
{
	# Last occurence of WIDTH:HEIGHT:X:Y from SlaveInput()
	WHXY="$(SlaveInput | grep rectangle | tail -1 | awk -F = '{print $2}')"

	# http://ffmpeg.org/ffmpeg-filters.html#crop
	CROPS="crop=${WHXY},"
}

ShiftSubtitleTimings()
{
	awk -v "offset=$STS" '
	function stamp2sec(timestamp) {
		split(timestamp,tfields,":")
		ret=0
		if (tfields[3]) {
			ret = tfields[1]*60*60 + tfields[2]*60 + tfields[3]
		} else if (tfields[2]) {
			ret = tfields[1]*60 + tfields[2]
		} else {
			ret = tfields[1]
		}
		return ret
	}
	function sec2stamp(time) {
		hour = sprintf("%d",time/(60*60))
		minute = sprintf("%d",time/60)
		sec = sprintf("%d",time)
		dec = sprintf("%d",time*100)%100
		return hour":"minute":"sec"."dec
	}
	BEGIN {FS=",";off=offset}
	{doprint=1}
	/\[Events\]/ { events=1 }
	events && /^Dialogue/ {
		doprint=1
		time=stamp2sec($2)
		if (time-off >= 0) {
			sub($2,sec2stamp(time-off))
			time=stamp2sec($3)
			sub($3,sec2stamp(time-off))
		} else { doprint=0 }
	}
	doprint {print}'
}

DetermineSubtitleFormat() {
	SUBTYPE="$(ffmpeg -i "$IF" 2>&1 | grep "#0:${STREAM}" | awk '{print $4}')"
}

HardsubOutput()
{
	# Dump fonts if there are any, and continue
	ffmpeg -v verbose -dump_attachment:t "" -i "$IF" -y 2>/dev/null || true

	mkdir -p "$FONTDIR"

	# Move dumped fonts to $FONTDIR if there are any, and continue
	mv -f ./*.otf ./*.ttf ./*.ttc "$FONTDIR" 2>/dev/null || true

	# Invoke ffmpeg, because mediainfo is a piece of shit, to grep
	# subtitles contained in file and two additional lines
	ffmpeg -v verbose -i "$IF" 2>&1 | grep -A2 Subtitle

	read -p "Stream number? [e.g. #0.3 would be 3] " STREAM

	DetermineSubtitleFormat

	if [[ "$SUBTYPE" = "subrip" ]] ; then
		# Dump subtitle stream from start of selection to end of selection
		ffmpeg -v verbose -ss "$(bc<<<"$STS - 30")" -i "$IF" -ss 30 -t "$TIME" \
			-an -vn -codec:s:${STREAM} srt webmsubsns.srt

		# Shift the subtitle timings with awk so we can use fastseek
		ShiftSubtitleTimings < webmsubsns.srt > webmsubs.srt

		# http://ffmpeg.org/ffmpeg-filters.html#subtitles-1
		SUBS=",subtitles=$(pwd)/webmsubs.srt"
	elif [[ "$SUBTYPE" = "mov_text" ]] || [[ "$SUBTYPE" = "tx3g" ]] ; then
		ffmpeg -v verbose -ss "$(bc<<<"$STS - 30")" -i "$IF" -ss 30 -t "$TIME" \
			-an -vn -codec:s:${STREAM} mov_text webmsubsns.ttxt

		ShiftSubtitleTimings < webmsubsns.ttxt > webmsubs.ttxt

		SUBS=",subtitles=$(pwd)/webmsubs.ttxt"
	elif [[ "$SUBTYPE" = "ass" ]] || [[ "$SUBTYPE" = "ssa" ]] ; then
		ffmpeg -v verbose -ss "$(bc<<<"$STS - 30")" -i "$IF" -ss 30 -t "$TIME" \
			-an -vn -codec:s:${STREAM} ass webmsubsns.ass

		ShiftSubtitleTimings < webmsubsns.ass > webmsubs.ass

		SUBS=",ass=$(pwd)/webmsubs.ass"
	else
		echo "Unsupported subtitle format" && exit 1
	fi
}

Encode()
{
	# http://trac.ffmpeg.org/wiki/FilteringGuide
	FILTERS="${ADDFILTERS}${CROPS}scale=${W}:${H}${SUBS}"

	# Do a 2-pass encode, throwing the first output into /dev/null
	# It may work with '-accurate_seek', but this works for now
	# See: https://ffmpeg.org/ffmpeg.html#Main-options
	ffmpeg -v verbose -ss "$STS" -i "$IF" -t "$TIME" -threads "$THREADS" \
		-quality best -slices "$SLICES" -auto-alt-ref 1 -lag-in-frames "$LAG" \
		-an -sn -fs "${MBLIMIT}M" -vf "$FILTERS" -c:v "$CODEC" $BITRATE \
		$ADDPARAMS -pass 1 -f webm /dev/null -y || true

	ffmpeg -v verbose -ss "$STS" -i "$IF" -t "$TIME" -threads "$THREADS" \
		-quality best -slices "$SLICES" -auto-alt-ref 1 -lag-in-frames "$LAG" \
		-an -sn -fs "${MBLIMIT}M" -vf "$FILTERS" -c:v "$CODEC" $BITRATE \
		$ADDPARAMS -pass 2 -f webm "$OF" -y || true
}

Cleanup()
{
	if [[ "$SUB" = true ]] ; then
		# Remove temporary font dir and subs
		rm -vrf "$FONTDIR"
		rm -v webmsubsns.*
		rm -v webmsubs.*
	fi

	if [[ "$XRECORD" = true ]] ; then
		# Remove screenrecorder output
		rm -v "$IF"
	fi

	rm -v "$LOG"
}

PrintVariables()
{
	echo "Input file: $IF"
	echo "Output file: $OF"
	echo "Starting time: ${ST}/${STS} seconds"
	echo "Ending time: ${ET}/${ETS} seconds"
	echo "Running time of output: $TIME seconds"
	echo "Bitrate was $BITRATE"
	echo "Slices: $SLICES, lag in frames: $LAG"
	echo "Threads: $THREADS, set option to one output was slightly cut off"
	echo "Filters used: $FILTERS"
	echo "Additional parameters: $ADDPARAMS"
}

if [[ "$XRECORD" = true ]] ; then
	ScreenRecorder
fi

if [[ -z "$IF" ]] ; then
	Usage && exit 1
fi

if [[ "$CUT" = true ]] ; then
	CutVideo
fi

if [[ -z "$OF" ]] ; then
	SetOutputFilename
fi

CalculateRunningTime
CalculateBitrate

if [[ "$CROP" = true ]] ; then
	CropOutput
fi

if [[ "$SUB" = true ]] ; then
	HardsubOutput
fi

Encode
Cleanup
PrintVariables