#!/bin/sh

# FIXME: Handle audio track in main input
# TODO: Handle audio as secondary input

set -e

INPUT=../src/omni/show0/earth.mp4
LOGO=../../content/icon_small.png

HOST=${1:-morla}
if [ "$HOST" = "$(hostname --short)" ]; then
	IP=127.0.0.1
else
	IP=$(host "$HOST" | grep -Po 'address \K\S+')
fi

FIRSTPORT=${2:-5002} # even number - next 3 ports used too

ITERATIONS=${3-0} # endless by default

HEIGHT=360

# * height steps and bitrates based on https://developer.apple.com/library/content/documentation/General/Reference/HLSAuthoringSpec/Requirements.html
# * speeds tuned to just below 100% cpu usage for each combination on a multi-core computer
# TODO: adjust height steps or bitrates for 4:3 aspect ratio
# TODO: resolve steps from source height using http://aarmstrong.org/tutorials/aspect-ratios-and-h264
# TODO: Externalize speeds to site-specific configfile
  if [ $HEIGHT -le 234 ]; then VBITRATE=145000; SPEED_VP8=2;
elif [ $HEIGHT -le 270 ]; then VBITRATE=365000; SPEED_VP8=2;
elif [ $HEIGHT -le 360 ]; then VBITRATE=730000; SPEED_VP8=3;
elif [ $HEIGHT -le 432 ]; then VBITRATE=1100000; SPEED_VP8=4;
elif [ $HEIGHT -le 540 ]; then VBITRATE=2000000; SPEED_VP8=5;
elif [ $HEIGHT -le 720 ]; then VBITRATE=3000000; SPEED_VP8=15;
fi

# based on http://www.webmproject.org/docs/encoder-parameters/#real-time-cbr-encoding-and-streaming
# + loop-in-filter trick based on http://video.stackexchange.com/a/16933
# + scale+watermark trick based on http://stackoverflow.com/a/10937357
# + scale to square pixels as needed
# + Add 1s latency (deadline)
# + Use same RTP payload types as GStreamer
ffmpeg -hide_banner -threads auto -re \
 -f lavfi -i "movie=filename=$INPUT:loop=$ITERATIONS, setpts=N/(FRAME_RATE*TB)" \
 -i "$LOGO" \
 -filter_complex \
 "[0:v]scale=iw*sar*$HEIGHT/ih:$HEIGHT,setsar=1[bg];
  [bg][1:v]overlay=main_w-overlay_w-20:main_h-overlay_h-20[v]" \
 -map '[v]' \
 -pix_fmt yuv420p \
 -codec:v vp8 -quality realtime -deadline 1000000 -cpu-used "$SPEED_VP8" \
 -b:v "$VBITRATE" -minrate "$VBITRATE" -maxrate "$VBITRATE" \
 -undershoot-pct 95 -bufsize $((6000*VBITRATE/1000)) -rc_init_occupancy $((4000*VBITRATE/1000)) \
 -max-intra-rate 0 \
 -qmin 4 -qmax 56 \
 -f rtp -payload_type 100 "rtp://$IP:$((FIRSTPORT+2))?pkt_size=1200"