ref: 9443899c13d7a00b1d8dc07fb14735379ea8f2d1
parent: f8dd6e1c6e4b2585ec7735acb26b126548b90319
author: cbagwell <cbagwell>
date: Fri Sep 17 20:46:08 EDT 2004
adding script
--- /dev/null
+++ b/scripts/crossfade.sh
@@ -1,0 +1,101 @@
+#!/bin/bash
+#
+# crossfade_cat.sh
+#
+# Original script from Kester Clegg. Mods by Chris Bagwell to show
+# more examples of sox features.
+#
+# Creates two new files that when played together have a crossfade
+# of $1 seconds. This means that $1/2 of the crossfade is in
+# the 1st file and $1/2 in the second file. Can be used to
+# make audio CD's with a 0 second pregap between songs to
+# have one song flow into the next; yet still be able to skip
+# around the CD with minimal loss of song.
+#
+# Filenames are specified as $2 and $3.
+#
+# By default, script fades out first file and fades in second file.
+# This makes sure that we can mix the two files together with
+# no clipping of audio. If that option is overridden then the
+# user must make sure no clipping can occur themselves.
+#
+# $4 is optional and specifies if a fadeout should be performed on
+# first file.
+# $5 is optional and specifies if a fadein should be performed on
+# second file.
+#
+# Crossfaded file $2 is prepended with cfo_ and $3 is prepended
+# with cfi_.
+
+SOX=../src/sox
+SOXMIX=../src/soxmix
+
+if [ "$3" == "" ]; then
+ echo "Usage: $0 crossfade_seconds first_file second_file [ fadeout ] [ fadein ]"
+ echo
+ echo "If a fadeout or fadein is not desire then specify \"no\" for that option"
+ exit 1
+fi
+
+fade_length=$1
+first_file=$2
+second_file=$3
+
+fade_first="yes"
+if [ "$4" != "" ]; then
+ fade_first=$4
+fi
+
+fade_second="yes"
+if [ "$5" != "" ]; then
+ fade_second=$5
+fi
+
+fade_first_opts=
+if [ "$fade_first" == "yes" ]; then
+ fade_first_opts="fade t 0 0:0:$fade_length"
+fi
+
+fade_second_opts=
+if [ "$fade_second" == "yes" ]; then
+ fade_second_opts="fade t 0:0:$fade_length"
+fi
+
+echo "crossfade and concatenate files"
+echo
+echo "Finding length of $first_file..."
+first_length=`$SOX "$first_file" 2>&1 -e stat | grep Length | cut -d : -f 2 | cut -f 1`
+echo "Length is $first_length seconds"
+
+trim_length=`echo "$first_length - $fade_length" | bc`
+crossfade_split_length=`echo "scale=2; $fade_length / 2.0" | bc`
+
+# Get crossfade section from first file and optionally do the fade out
+echo "Obtaining $fade_length seconds of fade out portion from $first_file..."
+$SOX "$first_file" -s -w fadeout.wav trim $trim_length $fade_first_opts
+# Get the crossfade section from the second file and optionally do the fade in
+echo "Obtaining $fade_length seconds of fade in portion from $second_file..."
+$SOX "$second_file" -s -w fadein.wav trim 0 $fade_length $fade_second_opts
+# Mix the crossfade files together at full volume
+echo "Crossfading..."
+$SOXMIX -v 1.0 fadeout.wav -v 1.0 fadein.wav crossfade.wav
+
+echo "Spliting crossfade into $crossfade_split_length lengths"
+$SOX crossfade.wav crossfade1.wav trim 0 $crossfade_split_length
+$SOX crossfade.wav crossfade2.wav trim $crossfade_split_length
+
+echo "Trimming off crossfade sections from original files..."
+
+$SOX "$first_file" -s -w song1.wav trim 0 $trim_length
+$SOX "$second_file" -s -w song2.wav trim $fade_length
+
+echo "Creating crossfade files"
+$SOX song1.wav crossfade1.wav "cfo_${first_file}.wav"+$SOX crossfade2.wav song2.wav "cfi_${second_file}.wav"+
+echo -e "Removing temporary files...\n"
+rm fadeout.wav fadein.wav crossfade.wav crossfade1.wav crossfade2.wav song1.wav song2.wav
+mins=`echo "$trim_length / 60" | bc`
+secs=`echo "$trim_length % 60" | bc`
+echo "The crossfade occurs at around $mins mins $secs secs in $first_file"
+