MRaudioStitcher

#! /opt/local/bin/bash
#-x
set -o errexit
#-----------------------------------------------------------------------------------------------
#-----------------------------------------------------------------------------------------------

#to be run in either /short[Start/End]...
#takes no arguments

#decides on a random fade time based on the length of the current file

#final file is named output.aiff and should be moved and renamed before running this script
#again or it will be overwritten!!

# https://github.com/MIB1700/MRaudioChopperStitcher/
#-----------------------------------------------------------------------------------------------
#-----------------------------------------------------------------------------------------------

num=1
sr=44100
sign=1

# touch fileOrder.txt

for file in *.aiff
do
	eval "$(ffprobe -v quiet -show_format -of flat=s=_ -show_entries stream=duration "$file")";
	duration=${format_duration%.*}; #bash can't do floating point math so truncate!


	if (( "$num" > 1 )); then

		#probability gate: change sign to negative 45% of the time
    	if (( $(( RANDOM % 100)) < 45 ));then

    		sign=$(( "$sign" * -1 ))
    	fi

		crossTime=$(( (RANDOM % ("$duration" / 2)) + ("duration" / 2) + ((RANDOM % 5) * "$sign") ))
		#calsulate num of samples
		crossFormat=$(( "$crossTime" * "$sr" ))
	fi

	if (( "$num" == 1 ));then

		lastFile="$file"

	elif (( "$num" == 2 ));then

		ffmpeg -y -i "$lastFile" -i "$file" -filter_complex acrossfade=ns="$crossFormat":c1=hsin:c2=hsin output.aiff

	elif (( "$num" > 2 ));then

		#make sure we don't use output.aiff as the second input file...
		#don't need to check for output2.aiff since it gets destroyed at the end of each loop
		if [[ "$file" != "output.aiff" ]] && [[ "$file" != "output2.aiff" ]]; then

			ffmpeg -y -i output.aiff -i "$file" -filter_complex acrossfade=ns="$crossFormat":c1=hsin:c2=hsin output2.aiff

			#overwrite output with output2... therefor allowing to keeping using output2
			mv output2.aiff output.aiff

		elif [[ "$file" = "output.aiff" ]] || [[ "$file" = "output2.aiff" ]]; then

			echo ""
			echo ""
			echo ""
			echo "DONE"
			echo ""
			echo ""

			if mv output.aiff "$(date '+%Y_%m_%d_%H_%M_%S')_newStitchedAudio.aiff"; then
				#double check that output.aiff is gone
				if [[ -e "output.aiff" ]]; then
					rm output.aiff
				fi
			fi

			exit 0
		fi
	fi

	((num++))
	# lastDuration="$duration"

done

if mv output.aiff "$(date '+%Y_%m_%d_%H_%M_%S')_newStitchedAudio.aiff"; then
	#double check that output.aiff is gone
	if [[ -e "output.aiff" ]]; then
		rm output.aiff
	fi
fi