Tools::Fades

NAME

Audio::Tools::Fades - Fading in & out algorithms.

DESCRIPTION

Fades is a collection of algorithms for fading in/ out audio files.

SYNOPSIS

        use Audio::Tools::Fades;

        my $up_to = 5;
        my @names = qw( in out );
        my $volume = 1;

        my $fades = new Audio::Tools::Fades;

        foreach my $type ( qw( linear exp invexp trig invtrig ) ) {
                for my $direction ( 0, 1 ) {
                        my $fade = $fades -> fade( $up_to, $direction, $type );
                        print "fade $names[$direction] type: $type;\n\t";
                        for my $sample ( 0 .. $up_to ) {
                                printf ' %2d->%2.2f', $sample, &$fade( $sample, $volume );
                        }
                        print "\n";
                }
        }

AUTHOR

Nick Peskett - nick@soup.demon.co.uk

METHODS

new

Returns a blessed Audio::Tools::Fades object.

        my $fades = new Audio::Tools::Fades;

fade

Returns a reference to a subroutine that is initialised to the length of samples the fade is to last for. The subroutine returned takes the current sample offset & the current sample value as parameters. In the example I have used sample value 1 so you can see the effect of the fade.

        my $fade = $fades -> fade( $length, $direction, $type );
        for my $sample ( 0 .. $length ) {
                printf ' %2d->%2.2f', $sample, &$fade( $sample, 1 );
        }
        print "\n";

Where;

        $length         = length of fade
        $direction      = 0 for in, 1 for out
        $type is one of;
                linear  = smooth gradient
                exp     = exponential (gets loud quickly)
                invexp  = inverse exponential (gets loud slowly)
                trig    = trigonomic, roughly in between linear & exp
                invtrig = inverse trigonomic