File Coverage

blib/lib/Audio/Digest/MP3.pm

Criterion	Covered	Total	%
statement	10	12	83.3
branch			n/a
condition			n/a
subroutine	4	4	100.0
pod			n/a
total	14	16	87.5

package Audio::Digest::MP3;

use 5.006;
use strict;
use warnings;

require Exporter;

our $VERSION = 0.10;
our @EXPORT_OK = qw(format_time digest_frames);
our @ISA = 'Exporter';

use MPEG::Audio::Frame;
use Digest;
use Carp;

sub scan {
    my $class = shift;
    my $file = shift;
    my $ctx = Digest->new(shift || 'MD5');
    open my($fh), "<", $file or croak "Can't open file \"$file\": $!";
    binmode $fh;
    my $frames = 0;
    my $seconds = 0;
    my $bytes = 0;
    my %histogram;
    while(my $frame = MPEG::Audio::Frame->read($fh)){
        $ctx->add($frame->asbin);
        $frames++;
        $seconds += $frame->seconds;
        $bytes += length $frame->asbin;
        $histogram{$frame->bitrate}++;
    }
    return bless [ $ctx->hexdigest, $seconds, $frames, $bytes, \%histogram ], $class;
}

use overload '""' => \&digest;
sub digest  { shift->[0] };
sub seconds { shift->[1] };
sub frames  { shift->[2] };
sub bytes   { shift->[3] };
sub histogram { shift->[4] };
sub cbr { 1 == keys %{&histogram} }
sub vbr { 1 < keys %{&histogram} }

sub bitrate {
    my $self = shift;
    my $seconds = $self->seconds or return undef;
    if($self->cbr) { return +(keys %{$self->histogram})[0] }
    (my $bitrate = sprintf "%.1f", ($self->bytes/$seconds)*8/1000) =~ s/\.0//;
    return $bitrate;
}

sub playing_time {
    my $seconds = (shift)->seconds;
    return format_time($seconds, @_);
}

sub format_time {
    my $seconds = shift;
    my $digits = shift;
    local *_ = \$seconds;
    if(defined $digits) {
        my $abbrev = $digits =~ s/^-//;
        $_ = sprintf "%.$digits\Ef", $_;
        s/\.?0+$// if $abbrev;
    }
    s<^(\d+)>{
        $1 < 3600 ?
        sprintf "%d:%02d", $1 / 60, $1 % 60
        : sprintf "%d:%02d:%02d", $1 / 3600, int($1 / 60) % 60, $1 % 60
      }e;
    return $_;
}

sub digest_frames {
    my $file = shift;
    my $ctx = Digest->new(shift || 'MD5');
    open my($fh), "<", $file or croak "Can't open file \"$file\": $!";
    binmode $fh;
    my @digest;
    while(my $frame = MPEG::Audio::Frame->read($fh)){
        $ctx->reset;
        $ctx->add($frame->asbin);
        push @digest, $ctx->hexdigest;
    }
    return wantarray ? @digest : \@digest;
}

1;

__END__