#!/bin/bash
#
# small helper for calculation bitrates and resolutions for
# videoencoding
#
# Copyright (c) 2003 Mathias Gumz <gumz@cs.uni-magdeburg.de>
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.



MODE="bitrate"
FPS="25"
COLOR="no"
AR="16/9"
BITRATE="800"
WIDTH="740"
HEIGHT="576"

INCREMENT="300"

display_help()
{
  cat << EOF

ABOUT

  avicalc is a small script to calculate some values which
  are very important for encoding videos: bitrate and resolution.

EOF
  display_usage
  cat << EOF

BPPS

  red     : < 0.10 : don't do it. please. i beg you!
  yellow  : < 0.15 : It will look bad.
  cyan    : < 0.20 : You will notice blocks, but it will look ok.
  green   : < 0.25 : It will look really good.
  white   : < 0.25 : It won't really improve visually.
  magenta : > 0.30 : Don't do that either - try a bigger resolution instead.

EXAMPLES

  calculate br for 5 minutes of the movie that
  will result in a 10mb - file:

    $> avicalc -m bitrate -s 10mb -d 300  -> 279kbit/s

  calculate the bpp for this movie:

    $> avicalc -c -m bpp -r 512x244 -c -b 279 ->  0.8 bpp

  last output should be displayed red for showing it
  wont look good for sure. so, display some more
  resolutions to getting near the final resolution:

    $> avicalc -c -m lr -b 279 -a 16/9

  now choose one of the cyan or (better) green marked
  resolutions for encoding the avi.

LINKS

  the main-source for this script:

    http://www.mplayerhq.hu/DOCS/tech/encoding-tips.txt


AUTHOR

  mathias gumz <gumz at cs.uni-magdeburg.de>

BUGS

  not yet known
EOF
}

display_usage()
{
  cat << EOF
SYNOPSIS

  avicalc [-Hh] [-c] [-m mode]
    [-s size -d duration]
    [-b bitrate [-f fps] [-a aspectration] [-r resolution]]

OPTIONS

  -h    display usage
  -H    display full help

  -m    mode (bitrate|bpp|lr)

        bitrate - calculates the needed
          br for a wanted endsize of
          an avi of a given length/duration

        bpp - calculates the bits per
          pixel-rate for a given resolution,
          bitrate and frames per second.

        bpb - calculates bits per block (16x16)
          for a given resolution, bitrate
          and frames per second.

        lr - display a lot of resolutions
          and the responding bpp's. enable
          colormode to see what would look
          ok.

        lb - display a lot of resolutions and
          the responding bpps/bpb for a list of
          bitrates

  -s    wanted size (x|xKB|xMB)
  -d    duration (in seconds)

  -b    bitrate (in kbit/s)
  -a    aspect ratio (16/9|4/3|1.33)
  -r    resolution (widthxheight)
  -f    fps (25 is default)

  -i    increment (for -m lb)
  -c    color mode

EOF
}


extract_resolution()
{
  WIDTH=`echo $1 | sed -e 's/[^[:digit:]]\+[[:digit:]]*$//g'`
  HEIGHT=`echo $1 | sed -e 's/^[[:digit:]]*[^[:digit:]]\+//g'`
}

# $1 - bpp * 10
# $2 - bpp - bits per pixel
# $3 - bpb - bits per block
# $4 - ar
output_bpp()
{
  if [ "$COLOR" == "yes" ]; then
    if [ "$1" -lt 10 ]; then
      echo -en "\033[01;31m"
    elif [ "$1" -lt 15 ]; then
      echo -en "\033[01;33m"
    elif [ "$1" -lt 20 ]; then
      echo -en "\033[01;36m"
    elif [ "$1" -lt 25 ]; then
      echo -en "\033[01;32m"
    elif [ "$1" -lt 30 ]; then
      echo -en "\033[01;37m"
    else
      echo -en "\033[01;35m"
    fi
  fi

  echo "${WIDTH}x${HEIGHT} bitrate: $BITRATE ar: $4 bpp: $2 bpb: $3"

  if [ "$COLOR" == "yes" ]; then
    echo -en "\033[00m"
  fi
}


# 
# read cmdlineoptions
#

while getopts ":hHm:r:b:f:d:i:s:ca:" opts
do
  case "$opts" in
    h ) display_usage; exit 0;;
    H ) display_help; exit 0;;

    m ) MODE="$OPTARG";;
    c ) COLOR="yes";;
    a ) AR="$OPTARG";;
    i ) INCREMENT="$OPTARG";;

    b ) BITRATE="$OPTARG";;
    s )
      val=`echo "$OPTARG" | sed -e 's/[[:alpha:]]*$//g'`
      unit=`echo "$OPTARG" | sed -e 's/^[[:digit:]]*\.*[[:digit:]]*//g'`
      case "$unit" in
        MB | mb ) SIZE=`echo "print 1024 * 1024 * $val" | bc`;;
        KB | kb ) SIZE=`echo "print 1024 * $val" | bc`;;
      esac
      ;;
    d ) DURATION="$OPTARG";;
    r ) extract_resolution "$OPTARG";;
    f ) FPS="$OPTARG";;
  esac
done


case "$MODE" in
  b | bitrate )
    br=`echo "print ($SIZE * 8)/($DURATION*1000)" | bc`
    echo "needed bitrate : $br kbits/s"
    ;;
  bpp | bpb )
    bpp=`echo "scale = 2;print ($BITRATE * 1000) / ( $WIDTH * $HEIGHT * $FPS )" | bc`
    bpb=`echo "scale = 2;print ($bpp * 256)" | bc`
    ar=`echo "scale = 2; print ($WIDTH / $HEIGHT )" | bc`
    output_bpp `echo "scale = 0; print $bpp * 100" | bc | sed -e 's/[[:punct:]]*[[:digit:]]*$//g'` "$bpp" "$bpb" "$ar"
    ;;

  lr )
      WIDTH=720
      while [ "$WIDTH" -gt 300 ]
      do
        HEIGHT=$(( (( `echo "scale = 2; print ($WIDTH / ($AR))" | bc | sed -e 's/[[:punct:]]*[[:digit:]]*$//g'`+1) / 16 ) * 16))
        bpp=`echo "scale = 2;print ($BITRATE * 1000) / ( $WIDTH * $HEIGHT * $FPS )" | bc`
        bpb=`echo "scale = 2;print ($bpp * 256)" | bc`
        ar=`echo "scale = 2; print ($WIDTH / $HEIGHT )" | bc`
        output_bpp `echo "scale = 0; print $bpp * 100" | bc | sed -e 's/[[:punct:]]*[[:digit:]]*$//g'` "$bpp" "$bpb" "$ar"
        WIDTH=$(( $WIDTH - 16 ))
      done
    ;;

  lb )
      BITRATE=300
      while [ "$BITRATE" -lt 3000 ]
      do
        bpp=`echo "scale = 2;print ($BITRATE * 1000) / ( $WIDTH * $HEIGHT * $FPS )" | bc`
        bpb=`echo "scale = 2;print ($bpp * 256)" | bc`
        ar=`echo "scale = 2; print ($WIDTH / $HEIGHT )" | bc`
        output_bpp `echo "scale = 0; print $bpp * 100" | bc | sed -e 's/[[:punct:]]*[[:digit:]]*$//g'` "$bpp" "$bpb" "$ar"
        BITRATE=$(( $BITRATE + $INCREMENT ))
      done
    ;;

esac