Simple time estimator for avconv, without any error checking

timeleft.sh

#!/bin/sh
#
# Simple time estimator for avconv, without any error checking
#
# Usage: timeleft.sh HH:MM:SS.nn SOURCE_FPS ENCODE_FPS TIME
#
# Notice: for fractional SOURCE_FPS multiply SOURCE_FPS to an integer
#         and ENCODE_FPS by the same factor, 
#             i.e. ENCODE_FPS=24.92 and SOURCE_FPS=5 => 2492 500
#
# Copyright (C) 2016 Heiko Schaefer <heiko@rangun.de>
#
#    This work is free. You can redistribute it and/or modify it under the
#    terms of the Do What The Fuck You Want To Public License, Version 2,
#    as published by Sam Hocevar. See http://www.wtfpl.net/ for more details.
#

DUR=`date +'%s' -d "1970-01-01 $1Z"`
REM=$(((((DUR-$4)*$2)+($3/2))/$3))

if [ $REM -ge 86400 ]; then
  DAY=1
else  
  DAY=0
fi

NOW=`date +'%s'`
FIN=$((NOW+REM))
PCT=$((((($4*100) + (DUR/2))/DUR)))

DTD=`date +"%F"`
DFN=`date -d @${FIN} +"%F"`

if [ $DAY -ne 0 ]; then
  TL="~$(((REM+1800)/3600)) hours"
  TF=`date -d @${FIN} +"%c"`
else
  TL=`date -u -d @${REM} +"%T"`
  
  if [ "$DTD" = "$DFN" ]; then
    TF=`date -d @${FIN} +"%T"`
  else
    TF=`date -d @${FIN} +"%c"`
  fi
fi

echo "$TL ($DUR) => $TF ($PCT %)"

exit 0