#!/bin/sh
#
# TODO: Set predictive GOP size for WebM (when tested that it works)

set -eu

# TODO: Externalize to site-specific configfile
[ $# -gt 0 ] || set -- morla 5002 -- dvcam ../../content/icon_small.png

##
## generic functions
##
exit1() {
	echo >&2 "ERROR: $1"
	exit 1
}
# shellcheck disable=SC2048,SC2059
echo_n() {
 printf -- "$*"
}
# shellcheck disable=SC2048,SC2059
printf_each() {
 skel=$1; shift
 for string in $*; do
  printf -- "$skel" "$string"
 done
}
uniqwords() {
 echo_n "$@" | tr ' ' '\012' | sort -u
}
valuedargcount() {
 nonempty=
 while [ $# -gt 0 ]; do
  [ -z "$1" ] || nonempty=$((nonempty+1))
  shift
 done
 echo_n "$nonempty"
}

while [ $# -gt 0 ]; do
	case $1 in
	  --)
		shift; break;;
	  *)
		if [ -z "${HOST:-}" ]; then
			HOST=$1
		elif [ -z "${FIRSTPORT:-}" ]; then
			FIRSTPORT=$1
		else
			exit1 "Too many arguments: Max. 2 about target"
		fi
		;;
	esac
	shift
done

# TODO: Externalize to site-specific configfile
[ $# -gt 0 ] || set -- dvcam ../../content/icon_small.png

AINPUT=
VINPUT=
WINPUT=
XINPUT=
while [ $# -gt 0 ]; do
	case $1 in
		alsa=*) ALSA=${1#*=}; AINPUT=$((AINPUT+1));;
		alsa) ALSA=default; AINPUT=$((AINPUT+1));;
		dvcam=*) DVCAM=${1#*=}; DEINT=${DEINT:-yadif}; XINPUT=$((XINPUT+1));;
		dvcam) DVCAM=auto; XINPUT=$((XINPUT+1));;
		dc=*) IIDC=${1#*=}; VINPUT=$((VINPUT+1));;
		dc) IIDC=/dev/fw1; VINPUT=$((VINPUT+1));;
		videofile=*) VFILE=${1#*=}; VINPUT=$((VINPUT+1));;
		*.ffv1|*.yuv|*.vp8|*.vp9) VFILE=$1; VINPUT=$((VINPUT+1));;
		container=*) XFILE=${1#*=}; XINPUT=$((XINPUT+1));;
		*.avi|*.dv|*.mkv|*.mov|*.mp4|*.nut|*.ogg|*.ogv|*.webm) XFILE=$1; XINPUT=$((XINPUT+1));;
		*.png) LOGO=$1; WINPUT=$((WINPUT+1));;
		--) shift; break;;
		*) exit1 "Unsupported input: $1";;
	esac
	shift
done

HOST=${HOST:-127.0.0.1}
if [ "$HOST" = "$(hostname --short)" ]; then
	IP=127.0.0.1
else
	IP=$(host "$HOST" | grep -Po 'address \K\S+')
fi

[ -n "$AINPUT$VINPUT$XINPUT" ] || exit1 "Too few arguments: Min. 1 A/V source"
[ -z "$AINPUT" ] || [ -z "$VINPUT" ] || [ -z "$XINPUT" ] || exit1 "Too many arguments: Max. 2 A/V sources"
[ -z "$AINPUT" ] || [ $AINPUT -eq 1 ] || exit1 "Too many arguments: Max. 1 audio source"
[ -z "$VINPUT" ] || [ $VINPUT -eq 1 ] || exit1 "Too many arguments: Max. 1 video source"
[ -z "$WINPUT" ] || [ $WINPUT -eq 1 ] || exit1 "Too many arguments: Max. 1 watermark source"
[ -z "$XINPUT" ] || [ $XINPUT -eq 1 ] || exit1 "Too many arguments: Max. 1 multimedia source"
[ -n "${NOAUDIO:-}" ] || [ -z "$AINPUT$XINPUT" ] || HASAUDIO=1
[ -n "${NOVIDEO:-}" ] || [ -z "$VINPUT$XINPUT" ] || HASVIDEO=1
[ "$AINPUT$VINPUT$XINPUT" = "1" ] || TWOSOURCES=1
VSTREAMINDEX=1
[ -n "$AINPUT" ] || VSTREAMINDEX=0

FIRSTPORT=${FIRSTPORT:-5002} # even number - next 7 ports used too

ACHANNELS=1
AFRAMERATE_SRC=48000
AFRAMERATE_OPUS=48000
AFRAMERATE_AAC=44100
ABITRATE_OPUS=48000
ABITRATE_AAC=64000

# FIXME: support multiple heights
HEIGHT=288
HEIGHTS_WEBM="$HEIGHT"
HEIGHTS_MPEG="$HEIGHT"

RATIO_NUM=4
RATIO_DEN=3

# * bitrates and bits in parens based on https://developer.apple.com/library/content/documentation/General/Reference/HLSAuthoringSpec/Requirements.html
#   + bits rounded up to include nearby modulo 16 formats
#   + best (i.e. high-modulo) 16:9 heights: 216 288 360 432 576 720
#   + best (i.e. high-modulo) 4:3 heights: 288 312 384 480 624 816
# * speeds tuned to just below 100% cpu usage for each combination on a multi-core computer
# TODO: Externalize speeds to site-specific configfile
RATIO_NUM=${RATION_NUM:-16}
RATIO_DEN=${RATION_DEN:-9}
WIDTH=${WIDTH:-$((HEIGHT*RATIO_NUM/RATIO_DEN))}
BITS=$((WIDTH*HEIGHT))
if [ $BITS -le 110592 ]; then # 234p → 97344
 VBITRATE=145000
 SPEED_X264=fast; SPEED_X264_ALONE=fast
 SPEED_VP8=3; SPEED_VP8_ALONE=2
elif [ $BITS -le 150528 ]; then # 270p → 129600
 VBITRATE=365000
 SPEED_X264=faster; SPEED_X264_ALONE=fast
 SPEED_VP8=4; SPEED_VP8_ALONE=2
elif [ $BITS -le 196608 ]; then # 360p → 172800
 VBITRATE=730000
 SPEED_X264=veryfast; SPEED_X264_ALONE=fast
 SPEED_VP8=5; SPEED_VP8_ALONE=3
elif [ $BITS -le 331776 ]; then # 432p → 331776
 VBITRATE=1100000
 SPEED_X264=ultrafast; SPEED_X264_ALONE=fast
 SPEED_VP8=8; SPEED_VP8_ALONE=4
elif [ $BITS -le 589824 ]; then # 540p → 518400
 VBITRATE=2000000
 SPEED_X264=toofast; SPEED_X264_ALONE=veryfast
 SPEED_VP8_ALONE=5
elif [ $BITS -le 921600 ]; then # 720p → 921600
 VBITRATE=3000000
 SPEED_X264=toofast; SPEED_X264_ALONE=ultrafast
 SPEED_VP8_ALONE=15
fi
[ toofast != "$SPEED_X264" ] || HEIGHTS_MPEG=
[ -n "$HEIGHTS_MPEG" ] || SPEED_VP8="$SPEED_VP8_ALONE"
[ -n "$HEIGHTS_WEBM" ] || SPEED_X264="$SPEED_X264_ALONE"

HEIGHTS=$(uniqwords "$HEIGHTS_WEBM $HEIGHTS_MPEG")

[ -z "${SAVEDIR:-}" ] || SAVESTEM="${SAVEDIR:-}/$(date +%Y%m%d-%H%M%S)"
[ -z "${SAVEDIR:-}" ] || export FFREPORT=file="$SAVESTEM.log"

filter_split_height() {
 heightcount=$(echo "$HEIGHTS" | wc --words)
 echo_n "[$VSTREAMINDEX:v]${DEINT:+$DEINT,}format=pix_fmts=yuv420p,split=$heightcount"
 printf_each '[s%s]' "$HEIGHTS"
}
filter_scale() { outstem=${1:-v};
 for height in $HEIGHTS; do
  echo_n "[s$height]scale=iw*sar*$height/ih:$height,setsar=1[$outstem$height]"
 done
}
filter_watermark() {
 for height in $HEIGHTS; do
  echo_n "[bg$height][$((VSTREAMINDEX+1)):v]overlay=main_w-overlay_w-20:main_h-overlay_h-20[v$height]"
 done
}
filter_split_codec() { heights_webm=$1; heights_mpeg=$2;
 codeccount=$(valuedargcount "$@")
 printf_each "[v%s]split=$codeccount$(printf_each '[v%swebm]' "$heights_webm")$(printf_each '[v%smpeg]' "$heights_mpeg")" "$HEIGHTS"
}

encode_opus() {
 echo_n "-codec:a libopus -ac $ACHANNELS -ar $AFRAMERATE_OPUS -b:a $ABITRATE_OPUS"
}
encode_aac() {
 echo_n "-codec:a aac -strict experimental -ac $ACHANNELS -ar $AFRAMERATE_AAC -b:a $((ACHANNELS*ABITRATE_AAC))"
}
encode_vp8() { bitrate=$1; speed=$2;
 echo_n "-codec:v vp8 -quality realtime -deadline 1000000 -cpu-used $speed \
 -b:v $bitrate -minrate $bitrate -maxrate $bitrate \
 -undershoot-pct 95 -bufsize $((6000*bitrate/1000)) -rc_init_occupancy $((4000*bitrate/1000)) \
 -max-intra-rate 0 \
 -qmin 4 -qmax 56 \
 -force_key_frames expr:gte(t,n_forced*2)"
}
encode_x264() { bitrate=$1; speed=$2;
 echo_n "-codec:v libx264 -preset $speed -tune zerolatency \
 -maxrate $bitrate -bufsize $((bitrate*2)) -crf 23 \
 -force_key_frames expr:gte(t,n_forced*2)"
}
tee_rtp() { stream=$1; pt=$2; port=$3;
 echo_n "[select=\'$stream\':f=rtp:payload_type=$pt]rtp://$IP:$port?pkt_size=1200"
}

# * scale+watermark trick based on http://stackoverflow.com/a/10937357
#   + scale to square pixels as needed
# * routing based on http://trac.ffmpeg.org/wiki/Creating%20multiple%20outputs#Teepseudo-muxer
# * VP8 encoding based on http://www.webmproject.org/docs/encoder-parameters/#real-time-cbr-encoding-and-streaming
#   + Add 1s latency (deadline)
# * Predictive GOP size preserving scene-change GOP based on https://superuser.com/a/1098329
# * Use same RTP payload types as GStreamer
ffmpeg -hide_banner -threads auto \
 ${ALSA:+-f alsa -sample_rate "$AFRAMERATE_SRC" -channels "$ACHANNELS" -thread_queue_size 2048 -i "$ALSA"} \
 ${DVCAM:+-f iec61883 -thread_queue_size 64 -i $DVCAM} \
 ${XFILE:+-re${SEEK:+ -ss $SEEK} -i "$XFILE"} \
 ${IIDC:+-f libdc1394 -video_size 640x480 -framerate 15 -thread_queue_size 256 -i "$IIDC"} \
 ${VFILE:+-re${SEEK:+ -ss $SEEK} -i "$VFILE"} \
 ${LOGO:+-i "$LOGO"} \
 ${HASVIDEO:+-filter_complex \
 "$(filter_split_height);
  $(filter_scale "${WINPUT:+bg}")${WINPUT:+${LOGO:+;
   $(filter_watermark)}};
  $(filter_split_codec "$HEIGHTS_WEBM" "$HEIGHTS_MPEG")" } \
 ${SAVEDIR:+\
 ${DVCAM:+-map $((0${ALSA:++1})) \
 -codec copy -f dv "$SAVESTEM.dv" }} \
 ${HEIGHTS_WEBM:+\
 ${HASAUDIO:+-map '0:a' }${HASVIDEO:+$(printf_each ' -map [v%swebm]' "$HEIGHTS_WEBM") } -shortest \
 ${HASAUDIO:+\
 $(encode_opus) } \
 ${HASVIDEO:+\
 $(encode_vp8 "$VBITRATE" "$SPEED_VP8") } \
 -f tee \
 "${HASAUDIO:+\
   $(tee_rtp a 111 "$FIRSTPORT")|\
  }${HASVIDEO:+\
   $(tee_rtp v 100 $((FIRSTPORT+2)))}" } \
 ${HEIGHTS_MPEG:+\
 ${HASAUDIO:+-map '0:a' }${HASVIDEO:+$(printf_each ' -map [v%smpeg]' "$HEIGHTS_MPEG") } -shortest \
 ${HASAUDIO:+\
 $(encode_aac) } \
 ${HASVIDEO:+\
 $(encode_x264 "$VBITRATE" "$SPEED_X264") } \
 -f rtp_mpegts rtp://$IP:10000 }