From 122f3c401f23f84799802c7b9667bda222646487 Mon Sep 17 00:00:00 2001
From: "B. Watson" <yalhcru@gmail.com>
Date: Wed, 8 Apr 2015 03:18:53 -0400
Subject: initial commit

---
 find_key | 176 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100755 find_key

(limited to 'find_key')

diff --git a/find_key b/find_key
new file mode 100755
index 0000000..485e728
--- /dev/null
+++ b/find_key
@@ -0,0 +1,176 @@
+#!/usr/bin/perl -w
+
+# Key detection. Uses libsndfile + its perl bindings, vamp-plugin-sdk,
+# qm-vamp-plugins, and mplayer (for decoding mp3 files, since sndfile
+# doesn't)
+
+# Output is the output from the qm-keydetector plugin (with its key numbers
+# converted to key names), followed by a list of all keys detected, sorted
+# descending by the amount of the song that was in that key.
+
+# The user is expected to understand what relative keys are: if 70% of the song
+# is in G and 30% is in E minor (same actual key, relative minor), it's up to
+# the user to listen to the song and decide whether it sounds more major or minor.
+
+# 20140107 bkw: hack to add support for anything SndFile can't read, by
+# using mplayer to convert to tmp.wav
+
+use Audio::SndFile;
+
+our @keynames = split /\s/, 'none C Db D Eb E F F# G Ab A Bb B Cm C#m Dm Ebm Em Fm F#m Gm G#m Am Bbm Bm none';
+
+our %relative_majors = (
+		'Cm' => 'Eb',
+		'C#m' => 'E',
+		'Dm' => 'F',
+		'Ebm' => 'F#',
+		'Em' => 'G',
+		'Fm' => 'Ab',
+		'F#m' => 'A',
+		'Gm' => 'Bb',
+		'G#m' => 'B',
+		'Am' => 'C',
+		'Bbm' => 'Db',
+		'Bm' => 'D',
+		);
+
+our %relative_minors = (
+		'Eb' => 'Cm',
+		'E' => 'C#m',
+		'F' => 'Dm',
+		'F#' => 'Ebm',
+		'G' => 'Em',
+		'Ab' => 'Fm',
+		'A' => 'F#m',
+		'Bb' => 'Gm',
+		'B' => 'G#m',
+		'C' => 'Am',
+		'Db' => 'Bbm',
+		'D' => 'Bm',
+		);
+
+if(!@ARGV || $ARGV[0] =~ /^--?h(elp)?/) {
+	print <<EOF;
+$0: Find key of music in audio (or maybe video) files.
+
+Usage: $0 [-m|-M] file.wav [file.wav ...]
+
+-m: Force all keys to minor
+-M: Force all keys to major
+EOF
+	exit 0;
+}
+
+for(@ARGV) {
+	if(/^-M/) {
+		$fold_major = 1;
+		$fold_minor = 0;
+		next;
+	} elsif(/^-m/) {
+		$fold_major = 0;
+		$fold_minor = 1;
+		next;
+	}
+
+	my $sec;
+	{
+		my $sf;
+		eval {
+			$sf = Audio::SndFile->open("<", $_);
+		};
+		if($@) {
+			warn "Extracting to tmp.wav\n";
+			system("mplayer -vo null -ao pcm:fast:file=tmp.wav \"$_\"");
+			$sf = Audio::SndFile->open("<", "tmp.wav");
+			$_ = "tmp.wav";
+		}
+		$sec = ($sf->frames) * (1 / $sf->samplerate);
+	}
+	printf "file is %03.2f sec\n", $sec;
+
+	my $oldstamp = -1;
+	my $oldkey = -1;
+
+	my $got = `vamp-simple-host qm-vamp-plugins:qm-keydetector "$_" 2`;
+	die "Analysis failed\n" unless defined $got;
+
+	print "\n";
+
+	my @got = split "\n", $got;
+## 	for my $line (@got) {
+## 		my ($pre, $post) = split(/:/, $line);
+## 		my $gotkey = $keynames[$post];
+## 		my $gotrel;
+## 		if($gotkey =~ /m$/) {
+## 			$gotrel = get_relative_major($gotkey);
+## 		} else {
+## 			$gotrel = get_relative_minor($gotkey);
+## 		}
+## 		$line =~ s/:\s(\d+)\s*/": $gotkey ($gotrel)"/e;
+## 		print $line . "\n";
+## 	}
+
+	for(@got) {
+		my ($key, $relkey);
+		s/^\s*//;
+		s/\s*$//;
+		my ($stamp, $keynum) = split /: /, $_;
+		$keynum =~ s/\s.*//;
+		$key = $keynames[$keynum];
+		if($fold_major) {
+			$key = get_relative_major($key);
+		} elsif($fold_minor) {
+			$key = get_relative_minor($key);
+		}
+		if($key =~ /m$/) {
+			$relkey = get_relative_major($key);
+		} else {
+			$relkey = get_relative_minor($key);
+		}
+		if($oldstamp != -1) {
+			$times{$oldkey} += ($stamp - $oldstamp);
+		}
+		$oldstamp = $stamp;
+		$oldkey = $key;
+		print "$stamp: $key ($relkey)\n";
+	}
+
+	$times{$oldkey} += ($sec - $oldstamp);
+
+	print "\n";
+	for(sort { $times{$b} <=> $times{$a} } keys %times) {
+		printf "%3s: %4.2f sec, %4.2f%%\n", $_, $times{$_}, $times{$_} / $sec * 100;
+	}
+}
+
+sub get_relative_major {
+	my $key = shift || die "missing key";
+	return $relative_majors{$key} || $key;
+}
+
+sub get_relative_minor {
+	my $key = shift || die "missing key";
+	return $relative_minors{$key} || $key;
+}
+
+__END__
+Output of plugin:
+- Estimated key (from C major = 1 to B major = 12 and C minor = 13 to B minor = 24)
+
+Looks like:
+ 0.000000000: 23
+ 54.984852607: 16
+ 59.443083900: 4
+ 71.331700680: 16
+ 78.019047619: 18
+ 78.762086167: 23
+ 95.108934240: 18
+ 97.338049886: 4
+ 110.712743764: 9
+ 112.198820861: 23
+ 210.279909297: 18
+ 215.481179138: 4
+ 216.967256235: 18
+ 222.168526077: 11
+ 231.084988662: 4
+ 234.057142857: 2
-- 
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