#!/bin/sh
# Copyright © 2010-2014, 2016 Jonas Smedegaard <dr@jones.dk>
# Description: Recode a video into web-optimized format(s)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Depends: ffmpeg melt mediainfo
# Recommends: moreutils vainfo vpx-tools vorbis-tools opus-tools
#
# TODO:
#  * Offer to skip rendering again if an output file exist already.
#  * Support --width and --height, resolving the other part from input
#    or forced aspect ratio.
#  * Check and fail if all needed tools are not available.
#  * Test if beneficial to apply real_time=-2.
#  * Normalize each infile separately when xml fed as infile keeps sync.
#    Maybe as workaround re-feed audio separately from xml, as done at
#    <http://bernaerts.dyndns.org/linux/74-ubuntu/214-ubuntu-stabilize-video-melt>.
#  * Resolve flash player to use.
#  * Make choice of encoders configurable.
#  * Figure out how to apply application option when using opusenc.
#  * Handle channels per-codec for low-bitrate joint stereo Opus speech.
#  * Double-check audio bandwidth algorithms:
#    http://trac.ffmpeg.org/wiki/Encode/HighQualityAudio
#  * Change WebM bandwidth algorithm:
#    Use https://developers.google.com/media/vp9/settings/vod/
#  * Tune VP8 parameters:
#    http://www.webmproject.org/docs/encoder-parameters/
#  * Tune VP9 parameters:
#    https://sites.google.com/a/webmproject.org/wiki/ffmpeg/vp9-encoding-guide
#  * Support DASH:
#    https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/instructions-to-playback-adaptive-webm-using-dash
#  * Support watermark
#  * Support live streaming - i.e. from (maybe faked) endless source
#    + Lipsync may require single stream of equally chunked tracks:
#      https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/instructions-to-do-webm-live-streaming-via-dash
#  * Support realtime streaming - i.e. with less than 200ms latency
#  * Compute (or hardcode) html5 codec types:
#    + Use mp4v2-utils
#    + http://stackoverflow.com/a/16365526

set -e

PRG=$(basename "$0")

showhelp() {
	cat <<EOF
Usage: $PRG [OPTION...] [--] [ARG=VALUE...] INPUTFILE... [ARG=VALUE...]
Encode video file in multiple web-optimized formats, and provide sample
html favoring open formats with optional non-JavaScript Flash fallback.

  --video           Video style:
                                   [refbpp]
                      talkinghead    0.1
                      action         0.15
                    (default: none)
  -p, --profile     Video frame size and optional rate, delimited by @
                    except "p" labels: e.g. 848x480@25 480p25 wvga@25
  -s, --size        Set video frame size:
                    [modulus 16]
                         320x240 qvga
                         640x480 vga          480p  848x480 wvga
                                              576p 1024x576 wsvga
                        1024x768 xga       hd 720p 1280x720 wxga
                    [modulus 8]
                                              240p  424x240 wqvga
                         480x360 hvga     nhd 360p  640x360
                         800x600 svga
                    (default: use input size)
  -a, --aspect      Display Aspect Ratio in melt format: e.g. @16/9
                    (default: no aspect hinting)
  -r, --rate        Video framerate: e.g. 25 1001/30000
                    (default: use input framerate)
  --refbpp          Bitrate reference: Bits-per-pixel for 360p30 H.264
                    (default: 0.12)
  --formats         Containers and codecs to use, comma-separated:
                                 [container] [video codec] [audio codec]
                      theora ogg    Ogg         Theora        Vorbis
                      vp8 webm      WebM        VP8           Vorbis
                      vp9           WebM        VP9           Opus
                      h264 mp4      MPEG-4      H.264         AAC
                    (default: webm,vp9,mp4)
  --audio           Audio style:
                              [channels] [bitrate per channel]
                      music    max. 2         ~48-64k
                      speech        1         ~32-64k
                      silence       0
                    (default: channel count of first input, ~48-64k)
  --audioprefilter  Add audio filter before loudness
  --loudness        Add EBU R128 loudness filter
  --loudness-data   Add loudness filter, with precomputed results
                    (default: none - compute results on-the-fly)
  --filter          Add filter
  --stem            Stem of output filenames, optionally with path
                    (default: basename of first input)
  -t, --title       Title used in html fallback graphics
                    (default: stem)
  --still-frame     Frame used as still picture
                    (default: 0)
  --sample          Create only a 150 frames long sample
  --sample-start    Create sample, starting at a specific frame
                    (default: start at first frame)
  --sample-length   Create sample of specified length, in frames
                    (default: 150 frames i.e. approx. 5s)
  --compression     Prioritize quality, size or render time:
                    (vp8 uses "soft-CQ" instead of unsupported Q)
                              [quality] [bitrate] [speed] [method,pass]
                      dirty                        fast        CQ,1
                      normal   medium    average   medium      CQ,1
                      hq       high      exact     very slow   CQ,2
                      exact    medium    exact     slow        CQ,2
                      quality  medium    vary      medium       Q,1
                    (default: normal)
  --quality         Quality rate factor: auto [integer] none
                      suggested, h264:        19  23  27  31  35  39
                      suggested, vp8/vp9:     27  33  39  45  51  57
                    (default: auto - 23 for h264, 33 for vp8/vp9)
  --gpu             Use hardware acceleration: none auto vaapi qsv
                    (default: auto when compression=dirty, else none)
  --gpudevice       Device used for hardware acceleration
                    (default: /dev/dri/renderD128)
  -h, --help        This help text

Examples:
  $PRG -s qvga -t "Funny guy" intro.dv myvideo.dv
  $PRG -p 480p15 --filter "grain noise=20" myvideo.dv

Recommendations for best results:
  * Use square pixels, modulus 16, max. 480 width (qvga vga 480p 720p).
  * Try lower --refbpp while visually acceptable, or raise to max. 0.2.
  * Expand and compress noisy speech with ladspa.1075 and ladspa.1916.

More info:
<http://camendesign.com/code/video_for_everybody>
<http://www.streaminglearningcenter.com/articles/configuring-your-streaming-video-(for-newbies).html>
<http://en.wikipedia.org/wiki/HTML5_video>
<http://www.penguinproducer.com/2012/01/ladspa-noise-removal/>
<http://theproaudiofiles.com/mixing-vocals-dynamics-compression-limiting>
<http://www.internetmarketingnotes.com/2010/07/free-embeddable-flash-video-flv-players-for-commercial-use/>
EOF
}

exit1() {
	response="${1:+Error: }${1:-Internal error!}"
	echo >&2 "$response"
	exit 1
}

# defaults
formats=webm,vp9,mp4
stillframe=0
samplestart=0
samplelength=150
compression=normal

# establish/verify rendering settings for reference codec
#
# 1) pick reference frame:encoding format: 360p30:h.264
# 2) pick reference codec (incl. normal settings)
# 3) render reference frame format with --compression=quality
#    * check that bpp is near "refbpp" of 0.12
#      (otherwise adapt settings or do research and update refbpp)
# 4) render misc. frame formats (esp. modulus 16) with --compression=quality
#    * check that bpp derives from refbpp by "rule of .75"
#      (otherwise adapt settings and/or do research and update rule)
# 5) render misc. frame formats with --compression=normal
#    * check that bpp derives from refbpp by "rule of .75"
# 6) optionally pick dirty/hq settings
#    * check that --compression=quality has filesize similar as normal

# establish/verify rendering settings for non-reference codec
#
# 1) pick normal settings
# 2) render reference frame format with --compression=quality
#    * check that this "codec-bpp" deviates reasonably from refbpp
# 3) render misc. frame formats (esp. modulus 16) with --compression=quality
#    * check that bpp derives from codec-bpp by "rule of .75"
#      (otherwise adapt settings and/or extend rule)
# 4) render misc. frame formats with --compression=normal
#    * check that bpp derives from codec-bpp by "rule of .75"
# 5) optionally pick dirty/hq settings
#    * check that --compression=quality has similar filesize as normal

# VP8 is rumored to compress ~20% worse than H.264
factor_vp8=120/100
# VP9 compresses ~30% better than H.264 for practical use-cases
# <https://engineering.fb.com/2018/04/10/video-engineering/av1-beats-x264-and-libvpx-vp9-in-practical-use-case/>
factor_vp9=70/100
# Mimic ReplayGain level when loudness is enabled (EBU R128: -23LUFS)
# <https://auphonic.com/blog/2013/01/07/loudness-targets-mobile-audio-podcasts-radio-tv/>
lufs=-18

# parse cmdline options
TEMP="`getopt -s sh -o hp:s:a:r:b:t: -l help,profile:,size:,aspect:,rate:,video:,refbpp:,formats:,audio:,audioprefilter:,loudness,loudness-data:,filter:,stem:,title:,still-frame:,sample,sample-start:,sample-length:,compression:,quality:,gpu:,gpudevice: -n "$PRG" -- "$@"`" || exit1 "Internal getopt error."
eval set -- "$TEMP"
while true ; do
	case "$1" in
	    -h|--help) showhelp; exit;;
	    -p|--profile) profile="$2"; shift 2;;
	    -s|--size) size="$2"; shift 2;;
	    -a|--aspect) aspect="$2"; shift 2;;
	    -r|--rate) framerate="$2"; shift 2;;
	    --video) video="$2"; shift 2;;
	    --refbpp) refbpp="$2"; shift 2;;
	    --formats) formats="$2"; shift 2;;
	    --audio) audio="$2"; shift 2;;
	    --audioprefilter) audioprefilters="${audioprefilters:+$audioprefilters }-filter $2"; shift 2;;
	    --loudness) loudness=yes; shift;;
	    --loudness-data) loudness=yes; loudness_data="$2"; shift 2;;
	    --filter) filters="${filters:+$filters }-filter $2"; shift 2;;
	    --stem) stem="$2"; shift 2;;
	    -t|--title) title="$2"; shift 2;;
	    --still-frame) stillframe="$2"; shift 2;;
	    --sample) sample=yes; shift;;
	    --sample-start) sample=yes; samplestart="$2"; shift 2;;
	    --sample-length) sample=yes; samplelength="$2"; shift 2;;
	    --compression) compression="$2"; shift 2;;
	    --quality) quality="$2"; shift 2;;
	    --gpu) gpu="$2"; shift 2;;
	    --gpudevice) gpudevice="$2"; shift 2;;
	    --) shift; break;;
	    *) exit1 "Internal error resolving options.";;
	esac
done

[ -n "$sample" ] || notsample=yes

# Resolve if system has many CPU cores
processors=$(nproc)
[ $processors -gt 2 ] || processors=

# sanitize infiles
infiles=$*
infile_first=$(perl -e 'print shift @ARGV' $infiles)
[ -e "$infile_first" ] || exit1 "Cannot read first input file \"$infile_first\"!"

# resolve stem and title (if not explicitly set)
stem=${stem:-$(basename "$infile_first" | perl -pe 's/\.[^.]*//')}
title=${title:-$stem}

#use_ffmpeg_vp8=yes
#use_ffmpeg_vp9=yes
#use_ffmpeg_h264=yes
#use_vpxenc=yes
# Avoid discrete audio encoders if possible: may cause sync problems
#use_oggenc=yes
#use_opusenc=yes
# Avoid AAC: Lame arguably better than any free AAC encoder
# Argument for AAC: Safari possibly lacks mp3 support in video container
#use_mp3=yes
[ -n "$use_mp3" ] || use_aac=yes

# Avoid MP3 VBR but seems ABR is fine: Set to CBR for strict correctnes
#use_lame_cbr=yes
[ -n "$use_lame_cbr" ] || use_lame_abr=yes

# resolve quality/speed hints
qkey_vp8=crf
qkey_vp9=crf
qkey_h264=crf
q_theora=5
q_vp8=33
cpu_vp8=2
q_vp9=33
cpu_vp9=2
q_h264=23
preset_h264=medium
profile_vp8=0
profile_vp9=0
profile_h264=baseline
case "$compression" in
    normal) :;;
    dirty)
	gpu=${gpu:-auto}
	q_theora=1
	cpu_vp8=4
	cpu_vp9=4
	preset_h264=veryfast
	;;
    hq)
	multipass=yes
	q_theora=6
	cpu_vp8=0
	cpu_vp9=1
	preset_h264=veryslow
	;;
    exact)
	multipass=yes
	;;
    quality)
	no_bitrate=yes
	;;
    *) exit1 "Unknown compression mode \"$compression\".";;
esac
case "$quality" in
    auto|'') :;;
    none) no_q=yes;;
    *) q=$quality;;
esac
gpudevice=${gpudevice:-/dev/dri/renderD128}
if [ auto = "$gpu" ]; then
	vainfo=$(vainfo --display drm --device "$gpudevice" 2>/dev/null | grep -Po 'Driver version:\s*\K.*')
	case "$vainfo" in
	    '') gpu=;;
	    *)
		for vformat in vp8 vp9 h264; do
			eval "no_gpu_decoder_$vformat=yes"
			eval "no_gpu_encoder_$vformat=yes"
		done
		case $(vainfo --display drm --device "$gpudevice" 2>/dev/null | grep -Po 'VAProfile\S+\s*:\s*VAEntrypointVLD') in
		    *VAProfileVP8Version0_3*) no_gpu_decoder_vp8=;;
		    *VAProfileVP9Profile0*) no_gpu_decoder_vp9=;;
		    *VAProfileH264ConstrainedBaseline*) no_gpu_decoder_h264=;;
		esac
		case $(vainfo --display drm --device "$gpudevice" 2>/dev/null | grep -Po 'VAProfile\S+\s*:\s*VAEntrypointEncSlice') in
		    *VAProfileVP8Version0_3*) no_gpu_encoder_vp8=;;
		    *VAProfileVP9Profile0*) no_gpu_encoder_vp9=;;
		    *VAProfileH264ConstrainedBaseline*) no_gpu_encoder_h264=;;
		esac
		if [ -n "$no_gpu_decoder_vp8$no_gpu_decoder_vp9$no_gpu_decoder_h264" ]; then
			case "$vainfo" in
# TODO			    *"Intel iHD driver"*) gpu=qsv;;
			    *) gpu=vaapi;;
			esac
		fi
	esac
fi
case "$gpu" in
    none|'') gpu=;;
    qsv)
	multipass=
	preset_vp8=medium
	preset_vp9=medium
	preset_h264=
	profile_h264=578
	qkey_h264=qp
	;;
    vaapi)
	multipass=
	preset_h264=
	profile_h264=578
	qkey_h264=qp
	case "$compression" in
	    dirty)
		preset_h264=
		;;
	esac
	;;
    *) exit1 "Unknown GPU type \"$gpu\".";;
esac
[ -n "$multipass" ] || singlepass=yes
[ -z "$gpu" ] && no_gpu=yes || eval "gpu_$gpu=yes"

# parse/resolve size and framerate
case "$profile" in
    '') :;;
    *@*)
	while read s r foo; do
		profilesize="${size:-$s}"
		framerate="${framerate:-$r}"
	done << EOF
$(echo "$profile" | perl -F@ -anE 'say join " ", @F')
EOF
	;;
    *p*)
	while read s r foo; do
		profilesize="${size:-${s}p}"
		framerate="${framerate:-$r}"
	done << EOF
$(echo "$profile" | perl -Fp -anE 'say join " ", @F')
EOF
	;;
    *)
	profilesize="$profile"
	;;
esac
size=${size:-$profilesize}
case "$size" in
    qvga) size=320x240;;
    hvga) size=480x360;;
    vga) size=640x480;;
    svga) size=800x600;;
    xga) size=1024x768;;
    240p|wqvga) size=424x240;;
    360p|nhd) size=640x360;;
    480p|wvga) size=848x480;;
    576p|wsvga) size=1024x576;;
    720p|wxga|hd) size=1280x720;;
esac
if [ -n "$size" ]; then
	while read w h foo; do
		width="${width:-$w}"
		height="${height:-$h}"
	done << EOF
$(echo "$size" | perl -Fx -anE 'say join " ", @F')
EOF
	if [ -z "$width" ] || [ -z "$height" ]; then
		exit1 "Failed to parse size \"$size\"."
	fi
fi
case "$framerate" in
    */*)
	while read n d foo; do
		framerate_num="${framerate_num:-$n}"
		framerate_den="${framerate_den:-$d}"
	done << EOF
$(echo "$framerate" | perl -F/ -anE 'say join " ", @F')
EOF
	;;
    ?*)
	framerate_num="$framerate"
	framerate_den=1
	;;
esac

# resolve input size and framerate (needed for computing bitrate)
while read w h r s foo; do
	width_in="${width_in:-$w}"
	height_in="${height_in:-$h}"
	framerate_in="${framerate_in:-$r}"
	scantype_in="${scantype_in:-$s}"
done << EOF
$(mediainfo --Inform="Video;%Width% %Height% %FrameRate% %ScanType%" \
	"$infile_first")
EOF
[ Progressive = "$scantype_in" ] || do_deinterlace=yes

case "$video" in
    talkinghead)
	refbpp="${refbpp:-0.1}"
	x264tune=film
	;;
    action)
	refbpp="${refbpp:-0.15}"
	x264tune=film
	;;
    '')
	refbpp="${refbpp:-0.12}"
	;;
    *) exit1 "Unknown video style \"$video\".";;
esac

for format in $(echo "$formats" | sed -e 's/,/ /g'); do
	case $format in
	    theora|ogg) ogg=yes;;
	    h264|mp4) mp4=yes;;
	    vp8|webm) webm=yes;;
	    vp9) vp9=yes;;
	    *) exit1 "Unknown format \"$format\".";;
	esac
done

_width="${width:-$width_in}"
_height="${height:-$height_in}"

if [ -n "$_width" ] && [ -n "$_height" ]; then
	_pixels="$((_width*_height))"
fi
_frames="${framerate:-$framerate_in}"

webm_qmin=0
webm_qmax=63
webm_lag=16
webm_tokenparts_log2=0
if [ -n "$_pixels" ] && [ $_pixels -ge $((1024*768)) ]; then
	webm_qmin=11
	webm_qmax=51
	webm_tokenparts_log2=2
	if [ -n "$_frames" ] && [ $_frames -gt 40 ]; then
		webm_lag=25
		profile_vp8=1
		profile_vp9=1
	fi
fi

# compute average bitrate from reference data and "power of .75" rule
if [ -n "$_pixels" ] && [ -n "$_frames" ]; then
	bitrate_h264=$(perl -E '$refsize=640*360;' \
		-E "say int( +(($_pixels/\$refsize)**0.75*\$refsize*$_frames*$refbpp) )")
	bitrate_theora=$bitrate_h264 # FIXME
	bitrate_vp8=$(perl -E "say int( +($bitrate_h264*$factor_vp8) )") #"
	bitrate_vp9=$(perl -E "say int( +($bitrate_h264*$factor_vp9) )") #"
fi

# default per-codec-channel bitrates
quality_vorbis=3
bitrate_opus=48
quality_lame=6
bitrate_lame=64
bitrate_aac=64

case "$audio" in
    music)
	opusapp=audio
	;;
    speech)
	mono=yes
	quality_vorbis=2
	bitrate_opus=32
	quality_lame=7
	bitrate_lame=48
	opusapp=voip
	;;
    silence)
	silence=yes
	;;
    '')
	:
	;;
    *) exit1 "Unknown audio style \"$audio\".";;
esac
which ffprobe > /dev/null && ffprobe=ffprobe || ffprobe=avprobe
channels=$($ffprobe -v warning -show_streams "$infile_first" \
	| perl -ne 's/channels=// and print $_' || echo -1)
# adapt channel count and flags to reflect actual downmix/silence need
if [ -n "$stereo" ]; then
	if [ $channels -gt 2 ]; then
		channels=2
	else
		stereo=
	fi
elif [ -n "$mono" ]; then
	if [ $channels -gt 1 ]; then
		channels=1
	else
		mono=
	fi
elif [ -n "$silence" ]; then
	if [ $channels -gt 0 ]; then
		channels=0
	else
		silence=
	fi
fi
[ -z "$silence" ] || channels=
if [ -n "$stereo$mono" ]; then
	# melt cannot downmix with (stereo?) filters applied (bug#763911)
	if [ -n "$audioprefilters$compress$loudness$limit$filters" ]; then
		if [ -z "${webm:+$use_oggenc}${webm_vp9:+$use_opusenc}" ]; then
			downmix_ffmpeg=yes
		else
			downmix_oggenc=yes
			downmix_oggenc=yes
		fi
	else
		downmix_melt=yes
	fi
fi

encoder_vp8=libvpx
encoder_vp9=libvpx-vp9
encoder_h264=libx264
for vformat in vp8 vp9 h264; do
	[ -z "$no_bitrate" ] || eval "no_bitrate_$vformat=yes"
	eval "[ -n \"$no_bitrate\$no_bitrate_$vformat\" ] || do_bitrate_$vformat=yes"
	eval "[ -z \"$no_q\$no_q_$vformat\" ] || q_$vformat="
	[ -z "$q" ] || eval "q_$vformat=$q"
	eval "[ -n \"\$q_$vformat\" ] || no_q_$vformat=yes"
	[ -z "$gpu" ] || eval "[ -n \"\$no_gpu_encoder_$vformat\" ] || encoder_$vformat=${vformat}_$gpu"

	# melt supports dual-pass only for h.264
	[ h264 = "$vformat" ] || [ -n "$use_vpxenc" ] || eval "[ -z \"$multipass\" ] || use_ffmpeg_$vformat=yes"
	# melt (before v6.26) does not support encode-only hardware acceleration
	[ h264 = "$vformat" ] || [ -n "$use_vpxenc$gpu_vaapi" ] || eval "[ -z \"$multipass\" ] || use_ffmpeg_$vformat=yes"
done
if [ -n "$use_ffmpeg_vp8$use_ffmpeg_vp9$use_vpxenc" ]; then
	[ -n "$use_oggenc" ] || use_ffmpeg_ogg=yes
	[ -n "$use_opusenc" ] || use_ffmpeg_opus=yes
	[ -z "$use_oggenc$use_opusenc" ] || use_wav=yes
	[ -z "$use_ffmpeg_ogg$use_ffmpeg_opus" ] || use_matroska=yes
fi
if [ -n "$use_ffmpeg_h264" ]; then
	use_matroska=yes
else
	use_melt_h264=yes
fi

[ -z "$gpu" ] || echo >&2 "GPU platform enabled: $gpu"

# gpu options
_melt_gpu_init=${gpu:+ ${gpu}_device=$gpudevice}
_ffmpeg_gpu_vaapi_init="-${gpu}_device $gpudevice"
_ffmpeg_gpu_qsv_init="-init_hw_device qsv=hw:$gpudevice -filter_hw_device hw"
_ffmpeg_gpu_init="${gpu_vaapi:+ ${_ffmpeg_gpu_vaapi_init}}${gpu_qsv:+ ${_ffmpeg_gpu_qsv_init}}"
_ffmpeg_gpu_vaapi_filter="-vf 'format=nv12|$gpu,hwupload'"
_ffmpeg_gpu_qsv_filter="-vf 'hwupload=extra_hw_frames=64,format=qsv'"
_ffmpeg_gpu_filter="${gpu_vaapi:+ ${_ffmpeg_gpu_vaapi_filter}}${gpu_qsv:+ ${_ffmpeg_gpu_qsv_filter}}"

# generic options
melt="melt -progress$_melt_gpu_init"
which ffmpeg > /dev/null && ffmpeg=ffmpeg || ffmpeg=avconv
ffmpeg_alone="$ffmpeg -threads auto -y -hide_banner -v info -stats$_ffmpeg_gpu_init"
ffmpeg_chained="$ffmpeg -threads auto -y -v warning$_ffmpeg_gpu_init"
vpxenc_chained="vpxenc --quiet ${processors:+-t $((processors-1))}"
oggenc="oggenc"
opusenc="opusenc"
_melt_infiles="${notsample:+$infiles}${sample:+$infile_first in=$((samplestart)) out=$((samplestart + samplelength))}"

# filter options
_melt_video="progressive=1${framerate:+ frame_rate_num="$framerate_num" frame_rate_den="$framerate_den"}${size:+ s=${width:+$width}x${height:+$height}}${aspect:+ aspect=$aspect}"
_ffmpeg_video="${no_gpu:+${do_deinterlace:+-filter:v yadif}${framerate:+ -r $framerate_num/$framerate_den}${size:+ -s ${width:+$width}x${height:+$height}}${aspect:+ -aspect $aspect}}"
_melt_downmix="${downmix_melt:+ac=$channels}"
_ffmpeg_downmix="${downmix_ffmpeg:+-ac $channels}"
# FIXME: how to downmix to stereo?
_oggenc_downmix="${downmix_oggenc:+${mono:+--downmix}}"
_opusenc_downmix="${downmix_opusenc:+${stereo:+--downmix-stereo}${mono:+--downmix-mono}}"
# limit (i.e. avoid peaks "clipping")
_melt_postfilters_audio="${limit:+-filter ladspa.1077}"

# codec bitrate options
_melt_bitrate_vp8="${do_bitrate_vp8:+ vb=$bitrate_vp8} minrate=$((bitrate_vp8/20)) maxrate=$((bitrate_vp8*12))"
_ffmpeg_bitrate_vp8="${do_bitrate_vp8:+-b:v $bitrate_vp8} -minrate $((bitrate_vp8/20)) -maxrate $((bitrate_vp8*12))"
_vpxenc_bitrate_vp8="--target-bitrate=$((bitrate_vp8/1000)) --minsection-pct=5 --maxsection-pct=1200"
_melt_bitrate_vp9="${do_bitrate_vp9:+ vb=$bitrate_vp9} minrate=$((bitrate_vp9/20)) maxrate=$((bitrate_vp9*12))"
_ffmpeg_bitrate_vp9="${do_bitrate_vp9:+-b:v $bitrate_vp9} -minrate $((bitrate_vp9/20)) -maxrate $((bitrate_vp9*12))"
_vpxenc_bitrate_vp9="--target-bitrate=$((bitrate_vp9/1000)) --minsection-pct=5 --maxsection-pct=1200"

# codec low-level options
_melt_misc_vp8="qmin=$webm_qmin qmax=$webm_qmax g=120 deadline=good cpu-used=$cpu_vp8${profile_vp8:+ vprofile=$profile_vp8} auto-alt-ref=1 lag-in-frames=$webm_lag arnr-maxframes=7 arnr-strength=5 arnr-type=centered"
_ffmpeg_misc_vp8="-qmin $webm_qmin -qmax $webm_qmax -g 120 -deadline good -cpu-used $cpu_vp8${profile_vp8:+ -profile:v $profile_vp8} -auto-alt-ref 1 -lag-in-frames $webm_lag -arnr-maxframes 7 -arnr-strength 5 -arnr-type centered"
_vpxenc_misc_vp8="--min-q=$webm_qmin --max-q=$webm_qmax --kf-max-dist=120 --good --cpu-used=$cpu_vp8${profile_vp8:+ --profile=$profile_vp8} --token-parts=$webm_tokenparts_log2 --auto-alt-ref=1 --lag-in-frames=$webm_lag --arnr-maxframes=7 --arnr-strength=5 --arnr-type=3"
_melt_misc_vp9="qmin=$webm_qmin qmax=$webm_qmax g=120 deadline=good cpu-used=$cpu_vp9${profile_vp9:+ vprofile=$profile_vp9} auto-alt-ref=1 lag-in-frames=$webm_lag arnr-maxframes=7 arnr-strength=5 arnr-type=centered"
_ffmpeg_misc_vp9="-qmin $webm_qmin -qmax $webm_qmax -g 120 -deadline good -cpu-used $cpu_vp9${profile_vp9:+ -profile:v $profile_vp9} -auto-alt-ref 1 -lag-in-frames $webm_lag -arnr-maxframes 7 -arnr-strength 5 -arnr-type centered"
_vpxenc_misc_vp9="--min-q=$webm_qmin --max-q=$webm_qmax --kf-max-dist=120 --good --cpu-used=$cpu_vp9${profile_vp9:+ --profile=$profile_vp9} --tile-columns=$webm_tokenparts_log2 --tile-rows=$webm_tokenparts_log2 --auto-alt-ref=1 --lag-in-frames=$webm_lag --arnr-maxframes=7 --arnr-strength=5 --arnr-type=3"

# codec options
# emulate VP8 Constant Quality using "loose" Constrained Quality
_melt_theora="vcodec=libtheora${bitrate_theora:+ vb=$bitrate_theora} qscale=$q_theora"
_melt_vp8="vcodec=$encoder_vp8${pre_vp8:+ vpreset=$pre_vp8}${preset_vp8:+ preset=$preset_vp8}${do_bitrate_vp8:+ $_melt_bitrate_vp8}${q_vp8:+ ${no_bitrate_vp8:+vb=$((bitrate_vp8*10)) }$qkey_vp8=$q_vp8} $_melt_misc_vp8"
_ffmpeg_vp8="-c:v $encoder_vp8${pre_vp8:+ -vpre $pre_vp8}${preset_vp8:+ preset $preset_vp8}${do_bitrate_vp8:+ $_ffmpeg_bitrate_vp8}${q_vp8:+ ${no_bitrate_vp8:+-b:v $((bitrate_vp8*10)) }-$qkey_vp8 $q_vp8} $_ffmpeg_misc_vp8"
_vpxenc_vp8="--codec=vp8${do_bitrate_vp8:+ $_vpxenc_bitrate_vp8} --end-usage=${no_q_vp8:+vbr}${q_vp8:+cq --cq-level=$q_vp8} $_vpxenc_misc_vp8"
_melt_vp9="vcodec=$encoder_vp9${pre_vp9:+ vpreset=$pre_vp9}${preset_vp9:+ preset=$preset_vp9}${do_bitrate_vp9:+ $_melt_bitrate_vp9}${q_vp9:+ ${no_bitrate_vp9:+vb=0 }$qkey_vp9=$q_vp9} $_melt_misc_vp9"
_ffmpeg_vp9="-c:v $encoder_vp9${pre_vp9:+ -vpre $pre_vp9}${preset_vp9:+ -preset $preset_vp9}${do_bitrate_vp9:+ $_ffmpeg_bitrate_vp9}${q_vp9:+ ${no_bitrate_vp9:+-b:v 0 }-$qkey_vp9 $q_vp9} $_ffmpeg_misc_vp9"
_vpxenc_vp9="--codec=vp9${do_bitrate_vp9:+ $_vpxenc_bitrate_vp9} --end-usage=${no_q_vp9:+vbr}${q_vp9:+cq --cq-level=$q_vp9} $_vpxenc_misc_vp9"
_melt_h264="vcodec=$encoder_h264${preset_h264:+ vpreset=$preset_h264}${profile_h264:+ vprofile=$profile_h264}${x264tune:+ tune=$x264tune}${do_bitrate_h264:+ maxrate=$bitrate_h264${no_gpu:+ bufsize=$((bitrate_h264*2))}}${q_h264:+ $qkey_h264=$q_h264} threads=0${no_gpu:+ movflags=+faststart}"
_ffmpeg_h264="-c:v $encoder_h264${preset_h264:+ -preset $preset_h264}${profile_h264:+ -profile:v $profile_h264}${x264tune:+ -tune $x264tune}${do_bitrate_h264:+ -maxrate $bitrate_h264${no_gpu:+ -bufsize $((bitrate_h264*2))}}${q_h264:+ -$qkey_h264 $q_h264}${no_gpu:+ -movflags +faststart}"
_melt_pcm="$_melt_downmix acodec=pcm_s16le"
_melt_vorbis="$_melt_downmix acodec=libvorbis aq=$quality_vorbis"
_ffmpeg_vorbis="$_ffmpeg_downmix -c:a libvorbis -aq $quality_vorbis"
_oggenc_vorbis="$_oggenc_downmix -q $quality_vorbis"
_melt_opus="$_melt_downmix acodec=libopus ab=$((channels*bitrate_opus))k${opusapp:+ application=$opusapp}"
_ffmpeg_opus="$_ffmpeg_downmix -c:a libopus -b:a $((channels*bitrate_opus))k${opusapp:+ -application $opusapp}"
_opusenc_opus="$_opusenc_downmix --bitrate $((channels*bitrate_opus))"
_melt_mp3="$_melt_downmix acodec=libmp3lame${use_lame_abr:+ aq=$quality_lame}${use_lame_cbr:+ ab=$((channels*bitrate_lame))k}"
_ffmpeg_mp3="$_ffmpeg_downmix -c:a libmp3lame${use_lame_abr:+ -q:a $quality_lame}${use_lame_cbr:+ -b:a $((channels*bitrate_lame))k}"
_melt_aac="$_melt_downmix acodec=aac ab=$((channels*bitrate_aac))k"
_ffmpeg_aac="$_ffmpeg_downmix -c:a aac -b:a $((channels*bitrate_aac))k"

# container options
_melt_stdout="-consumer avformat:pipe:1 f=yuv4mpegpipe $_melt_video pix_fmt=yuv420p an=1 audio_off=1"
_ffmpeg_stdin="-f yuv4mpegpipe -i pipe:0$_ffmpeg_gpu_filter"
_ffmpeg_rawvideo="-f rawvideo"
_melt_wav="f=wav $_melt_pcm vn=1 video_off=1"
_ffmpeg_wav_in="-f wav"
_oggenc_wav_in=
_opusenc_wav_in=
_melt_matroska_pcm="f=matroska $_melt_downmix $_melt_pcm vn=1 video_off=1"
_ffmpeg_matroska_pcm_in="-f matroska"
_melt_ogg="f=ogg $_melt_video $_melt_theora ${silence:+an=1 audio_off=1}${channels:+$_melt_vorbis}"
_ffmpeg_ogg_in="-f ogg"
_ffmpeg_ogg_vorbis="-f ogg -vn $_ffmpeg_vorbis"
_ffmpeg_ogg_opus="-f ogg -vn $_ffmpeg_opus"
_melt_webm="f=webm $_melt_video $_melt_vp8 ${silence:+an=1 audio_off=1}${channels:+$_melt_vorbis}"
_ffmpeg_webm="-f webm $_ffmpeg_video $_ffmpeg_vp8 ${silence:+-an}${channels:+ $_ffmpeg_vorbis}"
_ffmpeg_webm_in="-f webm"
_ffmpeg_webm_onlyvideo="-f webm $_ffmpeg_video $_ffmpeg_vp8 -an"
_ffmpeg_webm_keepvideo="-f webm $_ffmpeg_video -c:v copy ${silence:+-an}${channels:+$_ffmpeg_vorbis}"
_ffmpeg_webm_keepvideo_opus="-f webm $_ffmpeg_video -c:v copy ${silence:+-an}${channels:+$_ffmpeg_opus}"
_melt_webm_vp9="f=webm $_melt_video $_melt_vp9 ${silence:+an=1 audio_off=1}${channels:+$_melt_opus}"
_ffmpeg_webm_vp9="-f webm $_ffmpeg_video $_ffmpeg_vp9 ${silence:+-an}${channels:+$_ffmpeg_opus}"
_ffmpeg_webm_onlyvideo_vp9="-f webm $_ffmpeg_video $_ffmpeg_vp9 -an"
_melt_mp4="f=mp4 $_melt_video $_melt_h264 ${silence:+an=1 audio_off=1}${channels:+${use_mp3:+$_melt_mp3}${use_aac:+$_melt_aac}}"
_ffmpeg_mp4="-f mp4 $_ffmpeg_video $_ffmpeg_h264 ${silence:+-an}${channels:+${use_mp3:+$_ffmpeg_mp3}${use_aac:+$_ffmpeg_aac}}"
_ffmpeg_mp4_onlyvideo="-f mp4 $_ffmpeg_video $_ffmpeg_h264 -an"
_ffmpeg_mp4_keepvideo="-f mp4 $_ffmpeg_video -c:v copy ${silence:+-an}${channels:+$_ffmpeg_mp3}"
_ffmpeg_mp4_keepvideo_aac="-f mp4 $_ffmpeg_video -c:v copy ${silence:+-an}${channels:+$_ffmpeg_aac}"
_melt_img="f=image2 $_melt_video"

_melt_loudness="$loudness_data"
if [ -n "$loudness" ] && [ -z "$silence$_melt_loudness" ]; then
	echo >&2 "Analyzing audio dynamics..."
	$melt $_melt_infiles \
		$audioprefilters -filter loudness $filters \
		-consumer xml:$stem.xml video_off=1 all=1
	_melt_loudness="$(perl -n \
		-e 'm!<(property) name="results">([^<]+)</\1>! and print $2' \
		$stem.xml)"
	echo >&2 "Loudness data: $_melt_loudness"
fi

if [ -n "$multipass" ] && [ -n "${webm:+$use_vpxenc$use_ffmpeg_vp8$use_oggenc}${vp9:+$use_vpxenc$use_ffmpeg_vp9$use_opusenc}${mp4:+$use_ffmpeg_h264}" ]; then
	echo >&2 "Analyzing video complexity..."
	if [ -n "$use_vpxenc" ]; then
		$melt $_melt_infiles $filters $_melt_stdout \
			| pee \
			${webm:+"$vpxenc_chained - $_vpxenc_vp8 \
			-p 2 --pass=1 --fpf=${stem}_vp8.log -o /dev/null"} \
			${vp9:+"$vpxenc_chained - $_vpxenc_vp9 \
			-p 2 --pass=1 --fpf=${stem}_vp9.log -o /dev/null"} \
			${mp4:+${use_ffmpeg_h264:+$_ffmpeg_rawvideo $_ffmpeg_h264 -an \
			-pass 1 -passlogfile ${stem}_h264 /dev/null}}
	else
		$melt $_melt_infiles $filters $_melt_stdout \
			| $ffmpeg_chained $_ffmpeg_stdin \
			${webm:+$_ffmpeg_rawvideo $_ffmpeg_vp8 -an \
			-pass 1 -passlogfile ${stem}_vp8 /dev/null} \
			${vp9:+$_ffmpeg_rawvideo $_ffmpeg_vp9 -an \
			-pass 1 -passlogfile ${stem}_vp9 /dev/null} \
			${mp4:+${use_ffmpeg_h264:+$_ffmpeg_rawvideo $_ffmpeg_h264 -an \
			-pass 1 -passlogfile ${stem}_h264 /dev/null}}
		[ -z "$webm" ] || [ -n "$use_ffmpeg_vp8" ] || mv -f ${stem}_vp8-*.log ${stem}_vp8_2pass.log
		[ -z "$vp9" ] || [ -n "$use_ffmpeg_vp9" ] || mv -f ${stem}_vp9-*.log ${stem}_vp9_2pass.log
	fi
fi

if [ -n "${webm:+$use_vpxenc$use_ffmpeg_vp8$use_oggenc}${vp9:+$use_vpxenc$use_ffmpeg_vp9$use_opusenc}${mp4:+$use_ffmpeg_h264}" ]; then
	echo >&2 "Encoding video${channels:+ and extracting audio}, as discrete files..."
	$melt $_melt_infiles \
		${channels:+$audioprefilters \
			${_melt_loudness:+-filter loudness program=$lufs \
			results="$_melt_loudness"}} \
		$filters${channels:+ $_melt_postfilters_audio} \
		${ogg:+-consumer avformat:$stem.ogv $_melt_ogg} \
		${mp4:+${use_melt_h264:+-consumer avformat:$stem.mp4 $_melt_mp4}} \
		${channels:+${use_wav:+-consumer avformat:$stem.wav \
			$_melt_wav}} \
		${channels:+${use_matroska:+-consumer avformat:$stem.mkv \
			$_melt_matroska_pcm}} \
		$_melt_stdout \
		| pee \
		${webm:+${use_ffmpeg_vp8:+"$ffmpeg_chained \
			$_ffmpeg_stdin $_ffmpeg_webm_onlyvideo \
			${multipass:+-pass 2 -passlogfile ${stem}_vp8} \
			${stem}${channels:+_silent}.webm"}} \
		${webm:+${use_vpxenc:+"$vpxenc_chained - $_vpxenc_vp8 \
			${singlepass:+-p 1} \
			${multipass:+-p 2 --pass=2 --fpf=${stem}_vp8.log} \
			-o ${stem}${channels:+_silent}.webm"}} \
		${vp9:+${use_ffmpeg_vp9:+"$ffmpeg_chained \
			$_ffmpeg_stdin $_ffmpeg_webm_onlyvideo_vp9 \
			${multipass:+-pass 2 -passlogfile ${stem}_vp9} \
			${stem}_vp9${channels:+_silent}.webm"}} \
		${vp9:+${use_vpxenc:+"$vpxenc_chained - $_vpxenc_vp9 \
			${singlepass:+-p 1} \
			${multipass:+-p 2 --pass=2 --fpf=${stem}_vp9.log} \
			-o ${stem}_vp9${channels:+_silent}.webm"}} \
		${mp4:+${use_ffmpeg_h264:+"$ffmpeg_chained \
			$_ffmpeg_stdin $_ffmpeg_mp4_onlyvideo \
			${multipass:+-pass 2 -passlogfile ${stem}_h264} \
			${stem}${channels:+_silent}.mp4"}}
	if [ -n "${webm:+$use_vpxenc$use_ffmpeg_vp8$use_oggenc}" ] && [ -n "$channels" ]; then
		echo >&2 "Encoding Vorbis audio and muxing with VP8 video..."
		if [ -n "$use_oggenc" ]; then
			$oggenc $_oggenc_wav_in $_oggenc_vorbis -o - $stem.wav \
				| $ffmpeg_chained \
				$_ffmpeg_webm_in -i ${stem}_silent.webm \
				$_ffmpeg_ogg_in -i pipe:0 \
				$_ffmpeg_webm_keepvideo $stem.webm
		else
			$ffmpeg_alone $_ffmpeg_webm_in -i ${stem}_silent.webm \
				$_ffmpeg_matroska_wav_in -i $stem.mkv \
				$_ffmpeg_webm_keepvideo ${stem}.webm
		fi
	fi
	if [ -n "${vp9:+$use_vpxenc$use_ffmpeg_vp9$use_opusenc}" ] && [ -n "$channels" ]; then
		echo >&2 "Encoding Opus audio and muxing with WebM/VP9 video..."
		if [ -n "$use_opusenc" ]; then
			$opusenc $_opusenc_wav_in $_opusenc_opus -o - $stem.wav \
				| $ffmpeg_chained \
				$_ffmpeg_webm_in -i ${stem}_vp9_silent.webm \
				$_ffmpeg_ogg_in -i pipe:0 \
				$_ffmpeg_webm_keepvideo_opus ${stem}_vp9.webm
		else
			$ffmpeg_alone $_ffmpeg_webm_in -i ${stem}_vp9_silent.webm \
				$_ffmpeg_matroska_wav_in -i $stem.mkv \
				$_ffmpeg_webm_keepvideo_opus ${stem}_vp9.webm
		fi
	fi
	if [ -n "${mp4:+$use_ffmpeg_h264}" ] && [ -n "$channels" ]; then
		if [ -n "$use_mp3" ]; then
			echo "Encoding MP3 audio and muxing with h.264 video..."
			$ffmpeg_alone $_ffmpeg_mp4_in -i ${stem}_silent.mp4 \
				$_ffmpeg_matroska_wav_in -i $stem.mkv \
				$_ffmpeg_mp4_keepvideo ${stem}.mp4
		else
			echo "Encoding AAC audio and muxing with h.264 video..."
			$ffmpeg_alone $_ffmpeg_mp4_in -i ${stem}_silent.mp4 \
				$_ffmpeg_matroska_wav_in -i $stem.mkv \
				$_ffmpeg_mp4_keepvideo_aac ${stem}.mp4
		fi
	fi
else
	echo >&2 "Encoding video${channels:+ and audio}, at once..."
	$melt $_melt_infiles \
		${channels:+$audioprefilters \
			${_melt_loudness:+-filter loudness program=$lufs \
			results="$_melt_loudness"}} \
		$filters${channels:+ $_melt_postfilters_audio} \
		${ogg:+-consumer avformat:$stem.ogv $_melt_ogg} \
		${webm:+-consumer avformat:$stem.webm $_melt_webm \
			${multipass:+pass=2 passlogfile=${stem}_vp8}} \
		${vp9:+-consumer avformat:${stem}_vp9.webm $_melt_webm_vp9 \
			${multipass:+pass=2 passlogfile=${stem}_vp9}} \
		${mp4:+-consumer avformat:$stem.mp4 $_melt_mp4}
fi

# cleanup encoding cruft
rm -f $stem.xml $stem.wav $stem.mkv ${stem}_*.log ${stem}_*silent.webm

# JPEG preview
$melt $infile_first in=$stillframe out=$stillframe \
	-group $filters \
	-consumer avformat:$stem.jpg $_melt_img

__width="${_width:+ width=\"$_width\"}"
__height="${_height:+ height=\"$_height\"}"
# Flash object needs extra space for controllers
__heightplus=${_height:+ height=\"$((_height+4))\"}
_source_ogg="<source src=\"$stem.ogv\" type=\"video/ogg\" />"
_source_webm="<source src=\"$stem.webm\" type=\"video/webm\" />"
_source_vp9="<source src=\"${stem}_vp9.webm\" type='video/ogg; codecs=\"vp9, opus\"' />"
_source_mp4="<source src=\"$stem.mp4\" type=\"video/mp4\" />"
[ -z "$flashplayer" ] || flash=yes
[ -n "$mp4" ] || [ -z "$flash" ] || error1 "Cannot enable flash when mp4 format is disabled."
_object_flash="<object$__width$__heightplus type=\"application/x-shockwave-flash\" data=\"$flashplayer.swf\">"
_param_name="<param name=\"movie\" value=\"$flashplayer.swf\" />"
_param_flashvars="<param name=\"flashvars\" value=\"image=$stem.jpg&amp;file=$stem.mp4\" />"
__oggfile=${ogg:+open format <a href=\"$stem.ogv\">Ogg</a>}
__webmfile=${webm:+open format <a href=\"$stem.webm\">WebM (VP8)</a>}
__vp9file=${vp9:+open format <a href=\"${stem}_vp9.webm\">WebM (VP9/Opus)</a>}
__mp4file=${mp4:+closed format <a href=\"$stem.mp4\">MPEG-4</a>}

cat >"$stem.html" <<EOF
<!-- Video for Everybody, Kroc Camen of Camen Design -->
<video$__width$__height preload controls>
${mp4:+$_source_mp4
}${vp9:+$_source_vp9
}${webm:+$_source_webm
}${ogg:+$_source_ogg
}${flash:+$_object_flash
$_param_name
$_param_flashvars
}<img src="$stem.jpg"$__width$__height alt="$title"
 title="No video playback capabilities, please download the video below" />
${flash:+</object>
}</video>
<p><strong>Download Video:</strong><ul>
${vp9:+<li>$__vp9file
}${webm:+<li>$__webmfile
}${ogg:+<li>$__oggfile
}${mp4:+<li>$__mp4file
}</ul></p>
EOF