Outputs ffmpeg progress to console as percentage of work completed.

ffmpeg-progress

# Get video duration in frames
	duration=$(ffmpeg -i [filename] 2>&1 | sed -n "s/.* Duration: \([^,]*\), start: .*/\1/p")
	fps=$(ffmpeg -i [filename] 2>&1 | sed -n "s/.*, \(.*\) tbr.*/\1/p")
	hours=$(echo $duration | cut -d":" -f1)
	minutes=$(echo $duration | cut -d":" -f2)
	seconds=$(echo $duration | cut -d":" -f3)
	FRAMES=$(echo "($hours*3600+$minutes*60+$seconds)*$fps" | bc | cut -d"." -f1)

# Start ffmpeg, use awk to flush the buffer and remove carriage returns
	ffmpeg -i [filename] [options] [outputfile] 2>&1 | awk '1;{fflush()}' RS='\r\n'>[errorlog] &

# Get ffmpeg Process ID
	PID=$( ps -ef | grep "ffmpeg" | grep -v "grep" | awk '{print $2}' )

# While ffmpeg runs, process the log file for the current frame, display percentage progress
	while ps -p $PID>/dev/null  ; do
    		currentframe=$(tail -n 1 [errorlog] | awk '/frame=/ { print $2 }')
  		if [[ -n "$currentframe" ]]; then
  		PROG=$(echo "scale=3; ($currentframe/$FRAMES)*100.0" | bc)
  		echo PROGRESS: $PROG
  		sleep 1
  		fi
	done