Add midi2note() and the corresponding unittest.

src/python/essentia/utils.py

@@ -73,6 +73,9 @@ def hz2cents(arg1, arg2):
     return _essentia.hz2cents(_c.convertData(arg1, _c.Edt.REAL),
                               _c.convertData(arg2, _c.Edt.REAL) )
 
+def midi2note(arg):
+    return _essentia.midi2note( _c.convertData(arg, _c.Edt.INTEGER) )
+
 def equivalentKey(arg):
     return _essentia.equivalentKey( _c.convertData(arg, _c.Edt.STRING) )
 
@@ -98,6 +101,7 @@ def derivative(array):
             'mel2hz', 'hz2mel',
             'midi2hz', 'hz2midi',
             'hz2cents',
+            'midi2note',
             'postProcessTicks',
             'normalize', 'derivative',
             'equivalentKey', 'lin2log']

src/python/globalfuncs.cpp

@@ -426,6 +426,19 @@ hzToCents(PyObject* notUsed, PyObject* args) {
   return PyFloat_FromDouble( int(cents) );
 }
 
+static PyObject*
+midiToNote(PyObject* notUsed, PyObject* arg) {
+
+  if (!PyLong_Check(arg)) {
+    PyErr_SetString(PyExc_TypeError, (char*)"argument must be an integer");
+    return NULL;
+  }
+
+  std::string note = midi2note( long( PyLong_AsLong(arg) ) );
+  const char *c_note = note.c_str();
+  return PyString_FromString( c_note );
+}
+
 static PyObject*
 getEquivalentKey(PyObject* notUsed, PyObject* arg) {
   if (!PyString_Check(arg)) {
@@ -1040,6 +1053,7 @@ static PyMethodDef Essentia__Methods[] = {
   { "midi2hz",       midiToHz,         METH_O, "Converts a midi note number to frequency in Hz" },
   { "hz2midi",       hzToMidi,         METH_O, "Converts a frequency in Hz to a midi note number" },
   { "hz2cents",      hzToCents,        METH_VARARGS, "Converts a frequency in Hz to cents" },
+  { "midi2note",     midiToNote,       METH_O, "Converts a midi note number in the root note" },
   { "lin2db",        linToDb,          METH_O, "Converts a linear measure of power to a measure in dB" },
   { "db2lin",        dbToLin,          METH_O, "Converts a dB measure of power to a linear measure" },
   { "db2pow",        dbToPow,          METH_O, "Converts a dB measure of power to a linear measure" },

test/src/unittests/base/test_utils.py

@@ -123,6 +123,11 @@ def testHzToCents(self):
         expected_cents = 100
         self.assertAlmostEqual(expected_cents, hz2cents(midi2hz(midi), tuning))
 
+    def testMidiToNote(self):
+        midi = 69
+        expected_note = "A4"
+        self.assertEqual(expected_note, midi2note(midi))
+
 
 suite = allTests(TestUtils)