#!/bin/sh

# This needs a short video file (test.mp4), it will decode it to
# raw video (warning: this will use A LOT of disk space!) then
# it will try to encode it with a variety of codecs, to compare
# their speed, CPU usage, and overall efficiency.

# I wrote this script when I was trying to find out what would
# be a good "mezzanine codec" to transfer 1080p/30fps video over
# gigabit Ethernet as efficiently as possible, where "efficiency"
# here means: low CPU usage on the sending side and low latency.
# I ended up using HDMI out and an HDMI capture dongle (😅) but
# further testing seemed to show that H264 ultrafast/zerolatency
# could actually deliver even better results than the codecs I
# tested here. 🤷

init() {
  ffmpeg -i test.mp4 -c:v rawvideo -c:a copy test.nut
}

test_codec() {
  KEY=$(echo "$*" | sha256sum | cut -c1-8)
  CODEC=$1
  shift
  ARGS="$@"
  LOG=test-$KEY.log
  OUT=test-$KEY.nut
  [ -f $OUT ] && return
  ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1 test.nut > $LOG
  printf "CODEC=%s\nARGS=\"%s\"\n\n" "$CODEC" "$*" >> $LOG
  pv -cN input test.nut \
  | /bin/time -a -f "TIME_REAL=%e\nTIME_USER=%U\nTIME_SYS=%S\nCPU_PERCENT=%P\n" -o $LOG ffmpeg -i - -an -c:v $CODEC $ARGS -f nut - \
  | pv -cN output > $OUT
  stat test.nut --format "SIZE_INPUT=%s" >> $LOG
  stat $OUT     --format "SIZE_OUTPUT=%s" >> $LOG
  echo
  cat $LOG
}

test_codec ffv1
test_codec ffvhuff
test_codec prores
test_codec mjpeg
test_codec mjpeg -qscale:v 1
test_codec mjpeg -qscale:v 2
test_codec mpeg1video
test_codec mpeg1video -qscale:v 1
test_codec mpeg1video -qscale:v 2
test_codec mpeg2video
test_codec mpeg2video -qscale:v 1
test_codec mpeg2video -qscale:v 2