diff chordextract.cpp @ 158:55c2dacd0d34

Example program

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/chordextract.cpp	Fri Dec 05 10:45:27 2014 +0000
@@ -0,0 +1,146 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+  NNLS-Chroma / Chordino
+
+  Audio feature extraction plugins for chromagram and chord
+  estimation.
+
+  Centre for Digital Music, Queen Mary University of London.
+  This file copyright 2014 QMUL.
+    
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License as
+  published by the Free Software Foundation; either version 2 of the
+  License, or (at your option) any later version.  See the file
+  COPYING included with this distribution for more information.
+*/
+
+/*
+  Extract chords from an audio file, read using libsndfile.  Works by
+  constructing the plugin as a C++ class directly, and using plugin
+  adapters from the Vamp Host SDK to provide input.
+
+  You can compile this with e.g. the following (Linux example):
+
+  $ g++ -D_VAMP_PLUGIN_IN_HOST_NAMESPACE -O2 -ffast-math chordextract.cpp Chordino.cpp NNLSBase.cpp chromamethods.cpp viterbi.cpp nnls.c -o chordextract -lsndfile -lvamp-hostsdk -ldl
+
+  But the same idea should work on any platform, so long as the Boost
+  Tokenizer headers and the Vamp Host SDK library are available and
+  the _VAMP_PLUGIN_IN_HOST_NAMESPACE preprocessor symbol is defined
+  throughout.
+*/
+
+#define _VAMP_PLUGIN_IN_HOST_NAMESPACE 1
+
+#include <vamp-hostsdk/PluginInputDomainAdapter.h>
+#include <vamp-hostsdk/PluginBufferingAdapter.h>
+
+#include "Chordino.h"
+
+#include <sndfile.h>
+
+#include <iostream>
+#include <string>
+
+using namespace std;
+using namespace Vamp;
+using namespace Vamp::HostExt;
+
+int main(int argc, char **argv)
+{
+    const char *myname = argv[0];
+
+    if (argc != 2) {
+	cerr << "usage: " << myname << " file.wav" << endl;
+	return 2;
+    }
+
+    const char *infile = argv[1];
+
+    SF_INFO sfinfo;
+    SNDFILE *sndfile = sf_open(infile, SFM_READ, &sfinfo);
+
+    if (!sndfile) {
+	cerr << myname << ": Failed to open input file " << infile
+	     << ": " << sf_strerror(sndfile) << endl;
+	return 1;
+    }
+
+    Chordino *chordino = new Chordino(sfinfo.samplerate);
+    PluginInputDomainAdapter *ia = new PluginInputDomainAdapter(chordino);
+    ia->setProcessTimestampMethod(PluginInputDomainAdapter::ShiftData);
+    PluginBufferingAdapter *adapter = new PluginBufferingAdapter(ia);
+
+    int blocksize = adapter->getPreferredBlockSize();
+
+    // Plugin requires 1 channel (we will mix down)
+    if (!adapter->initialise(1, blocksize, blocksize)) {
+	cerr << myname << ": Failed to initialise Chordino adapter!" << endl;
+	return 1;
+    }
+
+    float *filebuf = new float[sfinfo.channels * blocksize];
+    float *mixbuf = new float[blocksize];
+
+    Plugin::FeatureList chordFeatures;
+    Plugin::FeatureSet fs;
+
+    int chordFeatureNo = -1;
+    Plugin::OutputList outputs = adapter->getOutputDescriptors();
+    for (int i = 0; i < int(outputs.size()); ++i) {
+	if (outputs[i].identifier == "simplechord") {
+	    chordFeatureNo = i;
+	}
+    }
+    if (chordFeatureNo < 0) {
+	cerr << myname << ": Failed to identify chords output!" << endl;
+	return 1;
+    }
+    
+    int frame = 0;
+    while (frame < sfinfo.frames) {
+
+	int count = -1;
+	if ((count = sf_readf_float(sndfile, filebuf, blocksize)) <= 0) break;
+
+	// mix down
+	for (int i = 0; i < blocksize; ++i) {
+	    mixbuf[i] = 0.f;
+	    if (i < count) {
+		for (int c = 0; c < sfinfo.channels; ++c) {
+		    mixbuf[i] += filebuf[i * sfinfo.channels + c] / sfinfo.channels;
+		}
+	    }
+	}
+
+	RealTime timestamp = RealTime::frame2RealTime(frame, sfinfo.samplerate);
+	
+	// feed to plugin: can just take address of buffer, as only one channel
+	fs = adapter->process(&mixbuf, timestamp);
+
+	chordFeatures.insert(chordFeatures.end(),
+			     fs[chordFeatureNo].begin(),
+			     fs[chordFeatureNo].end());
+
+	frame += count;
+    }
+
+    sf_close(sndfile);
+
+    // features at end of processing (actually Chordino does all its work here)
+    fs = adapter->getRemainingFeatures();
+
+    // chord output is output index 0
+    chordFeatures.insert(chordFeatures.end(),
+			 fs[chordFeatureNo].begin(),
+			 fs[chordFeatureNo].end());
+
+    for (int i = 0; i < (int)chordFeatures.size(); ++i) {
+	cerr << chordFeatures[i].timestamp.toString() << ": "
+	     << chordFeatures[i].label << endl;
+    }
+
+    delete adapter;
+}
+