Respect quantizePost=False when parsing raw MIDI

music21/converter/__init__.py

@@ -1041,6 +1041,11 @@ def parse(value: Union[bundles.MetadataEntry, bytes, str, pathlib.Path],
 
     `format` specifies the format to parse the line of text or the file as.
 
+    `quantizePost` specifies whether to quantize a stream resulting from MIDI conversion.
+    By default, MIDI streams qre quantized to the nearest sixteenth or triplet-eighth
+    (i.e. smaller durations will not be preserved).
+    `quarterLengthDivisors` sets the quantization units explicitly.
+
     A string of text is first checked to see if it is a filename that exists on
     disk.  If not it is searched to see if it looks like a URL.  If not it is
     processed as data.
@@ -1834,6 +1839,26 @@ def testParseMidiQuantize(self):
         for n in midiStream.recurse(classFilter='Note'):
             self.assertTrue(numberTools.almostEquals(n.quarterLength % 0.5, 0.0))
 
+    def testParseMidiNoQuantize(self):
+        '''
+        Checks that quantization is not performed if quantizePost=False.
+        Source MIDI file contains only: 3 16th notes, 2 32nd notes.
+        '''
+        fp = common.getSourceFilePath() / 'midi' / 'testPrimitive' / 'test15.mid'
+
+        # Establish first that quantizePost=False will make a difference given the current default
+        from music21.defaults import quantizationQuarterLengthDivisors
+        self.assertGreater(8, max(quantizationQuarterLengthDivisors))
+
+        streamFpNotQuantized = parse(fp, forceSource=True, quantizePost=False)
+        self.assertIn(0.875, streamFpNotQuantized.flat._uniqueOffsetsAndEndTimes())
+
+        # Also check raw data: https://github.com/cuthbertLab/music21/issues/546
+        with fp.open('rb') as f:
+            data = f.read()
+        streamDataNotQuantized = parse(data, quantizePost=False)
+        self.assertIn(0.875, streamDataNotQuantized.flat._uniqueOffsetsAndEndTimes())
+
     def testIncorrectNotCached(self):
         '''
         Here is a filename with an incorrect extension (.txt for .rnText).  Make sure that

music21/converter/subConverters.py

@@ -1006,15 +1006,25 @@ def parseData(self, strData, number=None):
         Get MIDI data from a binary string representation.
 
         Calls midi.translate.midiStringToStream.
+
+        Keywords to control quantization:
+        `quantizePost` controls whether to quantize the output. (Default: True)
+        `quarterLengthDivisors` allows for overriding the default quantization units
+        in defaults.quantizationQuarterLengthDivisors. (Default: (4, 3)).
         '''
         from music21.midi import translate as midiTranslate
-        self.stream = midiTranslate.midiStringToStream(strData)
+        self.stream = midiTranslate.midiStringToStream(strData, **self.keywords)
 
     def parseFile(self, fp, number=None, **keywords):
         '''
         Get MIDI data from a file path.
 
         Calls midi.translate.midiFilePathToStream.
+
+        Keywords to control quantization:
+        `quantizePost` controls whether to quantize the output. (Default: True)
+        `quarterLengthDivisors` allows for overriding the default quantization units
+        in defaults.quantizationQuarterLengthDivisors. (Default: (4, 3)).
         '''
         from music21.midi import translate as midiTranslate
         midiTranslate.midiFilePathToStream(fp, self.stream, **keywords)

music21/midi/translate.py

@@ -2101,6 +2101,11 @@ def midiFilePathToStream(filePath, inputM21=None, **keywords):
     return a :class:`~music21.stream.Score` object (or if inputM21 is passed in,
     use that object instead).
 
+    Keywords to control quantization:
+    `quantizePost` controls whether to quantize the output. (Default: True)
+    `quarterLengthDivisors` allows for overriding the default quantization units
+    in defaults.quantizationQuarterLengthDivisors. (Default: (4, 3)).
+
     >>> sfp = common.getSourceFilePath() #_DOCS_HIDE
     >>> fp = str(sfp / 'midi' / 'testPrimitive' / 'test05.mid') #_DOCS_HIDE
     >>> #_DOCS_SHOW fp = '/Users/test/music21/midi/testPrimitive/test05.mid'
@@ -2194,10 +2199,15 @@ def midiAsciiStringToBinaryString(midiFormat=1, ticksPerQuarterNote=960, tracksE
     return midiBinStr
 
 
-def midiStringToStream(strData):
+def midiStringToStream(strData, **keywords):
     r'''
     Convert a string of binary midi data to a Music21 stream.Score object.
 
+    Keywords to control quantization:
+    `quantizePost` controls whether to quantize the output. (Default: True)
+    `quarterLengthDivisors` allows for overriding the default quantization units
+    in defaults.quantizationQuarterLengthDivisors. (Default: (4, 3)).
+
     N.B. -- this has been somewhat problematic, so use at your own risk.
 
      >>> midiBinStr = (b'MThd\x00\x00\x00\x06\x00\x01\x00\x01\x04\x00'
@@ -2214,7 +2224,7 @@ def midiStringToStream(strData):
     mf = midiModule.MidiFile()
     # do not need to call open or close on MidiFile instance
     mf.readstr(strData)
-    return midiFileToStream(mf)
+    return midiFileToStream(mf, **keywords)
 
 
 def midiFileToStream(mf, inputM21=None, quantizePost=True, **keywords):
@@ -2228,6 +2238,11 @@ def midiFileToStream(mf, inputM21=None, quantizePost=True, **keywords):
 
     The `inputM21` object can specify an existing Stream (or Stream subclass) to fill.
 
+    Keywords to control quantization:
+    `quantizePost` controls whether to quantize the output. (Default: True)
+    `quarterLengthDivisors` allows for overriding the default quantization units
+    in defaults.quantizationQuarterLengthDivisors. (Default: (4, 3)).
+
     >>> import os
     >>> fp = common.getSourceFilePath() / 'midi' / 'testPrimitive' / 'test05.mid'
     >>> mf = midi.MidiFile()
@@ -2251,6 +2266,9 @@ def midiFileToStream(mf, inputM21=None, quantizePost=True, **keywords):
     if not mf.tracks:
         raise exceptions21.StreamException('no tracks are defined in this MIDI file.')
 
+    if 'quantizePost' in keywords:
+        quantizePost = keywords.pop('quantizePost')
+
     # create a stream for each tracks
     # may need to check if tracks actually have event data
     midiTracksToStreams(mf.tracks,