flac2opus.pl

#!/usr/bin/env perl

use strict;
use warnings;

use Capture::Tiny;
use File::Which;
use Getopt::Std;
use Path::Tiny;

my $path = $ARGV[0] or HELP_MESSAGE();
my %opt;
Getopt::Std::getopt('b:', \%opt);
my $metaflac = File::Which::which('metaflac') or die "Cannot find metaflac\n";
my $opusenc = File::Which::which('opusenc') or die "Cannot find opusenc\n";
my @files;
if (-d $path) {
	@files = Path::Tiny->new($path)->children(qr/\.flac/);
}
elsif (-f $path) {
	@files = Path::Tiny->new($path);
};
foreach my $file (@files) {
	encode($file);
};

sub encode {
	my $file_in = shift;

	if (-f $file_in) {
		my ($stdout) = Capture::Tiny::capture {
			system($metaflac, '--export-tags=-', $file_in);
		};
		my %tags;
		foreach my $ln (split("\n", $stdout // '')) {
			my ($key, $val) = split("=", $ln, 2);
			next if $key !~ /^(title|artist|album|genre|date)$/i;
			$tags{'--'.lc($key)} = $val;
		};
		my $file_out = $file_in;
		$file_out =~ s/\.flac/\.opus/;
		system($opusenc, '--bitrate', $opt{'b'} // 160, %tags, $file_in, $file_out);
	};
}

sub HELP_MESSAGE {
	print qq/$0 [-b <bitrate>] <path|files>\n/;
	exit 1;
}