Allows bpm-tag to operate on m4a files.

Tags are written using mp4tags and read using mp4info, both of
which are part of the mp4v2 project, whose code is available at
https://code.google.com/p/mp4v2/

Makefile

@@ -4,6 +4,9 @@ PREFIX ?= /usr/local
 INSTALL ?= install
 
 BINDIR ?= $(PREFIX)/bin
+MANDIR ?= $(PREFIX)/share/man
+
+CFLAGS ?= -O3
 
 CFLAGS += -Wall
 LDLIBS += -lm
@@ -18,6 +21,8 @@ clean:
 install:
 	$(INSTALL) -d $(DESTDIR)$(BINDIR)
 	$(INSTALL) -t $(DESTDIR)$(BINDIR) bpm bpm-graph bpm-tag
+	$(INSTALL) -d $(DESTDIR)$(MANDIR)/man1
+	$(INSTALL) -t $(DESTDIR)$(MANDIR)/man1 bpm.1 bpm-graph.1 bpm-tag.1
 
 dist:
 	mkdir -p dist

README

@@ -1,6 +1,6 @@
 bpm-tools: Tempo (Beats Per Minute) analysis tools
 
-(C) Copyright 2012 Mark Hills <mark@xwax.org>
+(C) Copyright 2013 Mark Hills <mark@xwax.org>
 
 See the COPYING file for licensing terms.
 

bpm-graph

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright (C) 2012 Mark Hills <mark@xwax.org>
+# Copyright (C) 2013 Mark Hills <mark@xwax.org>
 #
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License
@@ -21,22 +21,37 @@
 # View graph of BPM analysis
 #
 
-set -e
+set -eu
 
-if [ -z "$1" ]; then
-	echo "Usage: $0 <file>" >&2
+usage()
+{
+	cat <<END
+bpm-graph (C) Copyright 2013 Mark Hills <mark@xwax.org>
+
+Usage: bpm-graph <file>
+Display tempo analysis data
+
+See the bpm-graph(1) man page for more information.
+END
+}
+
+if [ -z "${1-}" ] || [ "$1" = "-h" ]; then
+	usage >&2
 	exit 1
 fi
 
-set -u
-
 FILE="$1"
 shift
 
+if ! which gnuplot > /dev/null 2>&1; then
+	echo "$0: requires gnuplot to be installed" >&1
+	exit 1
+fi
+
 TMP=`mktemp -t bpm.XXXXXX` || exit 1
 trap "rm $TMP" 0
 
-sox "$FILE" -r 44100 -e float -c 1 -t raw - | bpm -m 60 -x 180 -g $TMP
+sox "$FILE" -r 44100 -e float -c 1 -t raw - | bpm -m 60 -x 220 -g $TMP
 gnuplot -p <<END
 set style data lines
 set ylabel "Difference"

bpm-graph.1

@@ -0,0 +1 @@
+.so man1/bpm-graph.1

bpm-tag

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright (C) 2012 Mark Hills <mark@xwax.org>
+# Copyright (C) 2013 Mark Hills <mark@xwax.org>
 #
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License
@@ -26,7 +26,7 @@ set -e
 usage()
 {
 	cat <<END
-bpm-tag (C) Copyright 2012 Mark Hills <mark@xwax.org>
+bpm-tag (C) Copyright 2013 Mark Hills <mark@xwax.org>
 
 Usage: bpm-tag [options] <file>
 Tag an audio file with tempo (in beats-per-minute, BPM)
@@ -37,6 +37,7 @@ Tag an audio file with tempo (in beats-per-minute, BPM)
   -x   Maximum detected BPM
   -h   Display this help message and exit
 
+See the bpm-tag(1) man page for more information and examples.
 END
 }
 
@@ -92,6 +93,9 @@ case "$FILE" in
 *.ogg)
 	BPM=`vorbiscomment "$FILE" | sed -n 's/^BPM=//p'`
 	;;
+*.m4a)
+	BPM=`mp4info "$FILE" | sed -n 's/^\s*BPM://p'`
+	;;
 *)
 	echo "$FILE: file extension not known" >&2
 	exit 1
@@ -128,6 +132,9 @@ case "$FILE" in
 *.ogg)
 	vorbiscomment -at "BPM=$BPM" "$FILE"
 	;;
+*.m4a)
+	mp4tags -tempo "$BPM" "$FILE"
+	;;
 *)
 	echo "$FILE: don't know how to tag this type of file" >&2
 	exit 1

bpm-tag.1

@@ -0,0 +1 @@
+.so man1/bpm.1

bpm.1

@@ -0,0 +1,73 @@
+.TH BPM "1"
+
+.SH NAME
+bpm-tools \- calculate the tempo of music files
+
+.SH SYNOPSIS
+.B bpm-tag
+[\fIoptions\fR] \fIfile\fR
+
+.B bpm-graph
+\fIfile\fR
+
+.B bpm
+[\fIoptions\fR] < \fIfile.raw\fR
+
+.SH DESCRIPTION
+
+The
+.B bpm-tools
+commands are used to automatically calculate the tempo (in
+beats-per-minute) of music, optionally displaying an analysis
+and adding it to file 'tags'. The data from these tags can be
+especially useful for navigating a music library in DJ software
+such as
+.B xwax(1).
+
+The
+.B bpm
+command implements the algorithm on raw data, but
+the most commonly used command is
+.B bpm-tag.
+
+.SH OPTIONS
+
+Options are described by the commands themselves. Use one of the
+following for more information:
+.sp
+.RS
+bpm-tag -h
+
+bpm-graph -h
+
+bpm -h
+.RE
+
+.SH EXAMPLES
+
+.P
+Tag a file with its tempo:
+.sp
+.RS
+bpm-tag "Daft Punk - Get Lucky.mp3"
+.RE
+
+.P
+Calculate and display the tempo of a file without modifying it:
+.sp
+.RS
+bpm-tag -f -n "Gwen Guthrie - Padlock.flac"
+.RE
+
+.P
+Tag a file, with a hint to look for a fast tempo:
+.sp
+.RS
+bpm-tag -m 120 -x 200 "Roni Size - Brown Paper Bag.oga"
+.RE
+
+.SH HOMEPAGE
+http://www.pogo.org.uk/~mark/bpm-tools/
+
+.SH AUTHOR
+Mark Hills <mark@xwax.org>

bpm.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@xwax.org>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -25,7 +25,7 @@
 #include <sysexits.h>
 #include <unistd.h>
 
-#define BANNER "bpm (C) Copyright 2012 Mark Hills <mark@xwax.org>"
+#define BANNER "bpm (C) Copyright 2013 Mark Hills <mark@xwax.org>"
 #define NAME "bpm"
 
 #define RATE 44100 /* of input data */
@@ -141,6 +141,7 @@ double scan_for_bpm(float nrg[], size_t len,
 	step = (slowest - fastest) / steps;
 
 	height = INFINITY;
+	trough = NAN;
 
 	for (interval = fastest; interval <= slowest; interval += step) {
 		double t;
@@ -186,7 +187,7 @@ void usage(FILE *f)
 		RATE, RATE);
 
 	fprintf(f, "To view autodifference or energy data:\n"
-		"  $ sox [...] | ./tempo -g file.dat\n"
+		"  $ sox [...] | " NAME " -g file.dat\n"
 		"  $ gnuplot\n"
 		"  gnuplot> plot \"file.dat\"\n\n");
 }