Merge pull request #18 from thunn/thunn/add_convert_for_frequency_to_…

…midi

Thunn/add convert for frequency to midi

.github/workflows/run-tests.yml

@@ -0,0 +1,31 @@
+name: run
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.8", "3.10"]
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install base dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e .
+          pip install soundfile pytest
+      - name: Run core tests
+        run: |
+          python -m pytest --ignore test/test_convert.py
+      - name: Install additional test dependencies
+        run: |
+          pip install -e '.[test]'
+      - name: Run all tests
+        run: |
+          python -m pytest

penn/convert.py

@@ -45,6 +45,21 @@ def frequency_to_samples(frequency, sample_rate=penn.SAMPLE_RATE):
     """Convert frequency in Hz to number of samples per period"""
     return sample_rate / frequency
 
+def frequency_to_midi(frequency):
+    """
+    Convert frequency to MIDI note number(s)
+    Based on librosa.hz_to_midi(frequencies) implementation
+    https://librosa.org/doc/main/_modules/librosa/core/convert.html#hz_to_midi
+    """
+    return 12 * (torch.log2(frequency) - torch.log2(torch.tensor(440.0))) + 69
+
+def midi_to_frequency(midi):
+    """
+    Convert MIDI note number to frequency
+    Based on librosa.midi_to_hz(notes) implementation
+    https://librosa.org/doc/main/_modules/librosa/core/convert.html#midi_to_hz
+    """
+    return 440.0 * (2.0 ** ((midi - 69.0) / 12.0))
 
 ###############################################################################
 # Time conversions

setup.py

@@ -19,6 +19,9 @@
             'pyworld',     # 0.3.2
             'scipy',       # 1.9.3
             'torchcrepe'   # 0.0.17
+        ],
+        'test': [
+            'librosa',     # 0.9.1
         ]
     },
     install_requires=[

test/test_convert.py

@@ -0,0 +1,32 @@
+import penn
+
+import librosa
+import torch
+
+
+###############################################################################
+# Test convert.py
+###############################################################################
+
+
+def test_convert_frequency_to_midi():
+    """Test that conversion from Hz to MIDI matches librosa implementation"""
+
+    sample_data = torch.tensor([110.0, 220.0, 440.0, 500.0, 880.0])
+
+    penn_midi = penn.convert.frequency_to_midi(sample_data)
+
+    librosa_midi = librosa.hz_to_midi(sample_data.numpy())
+
+    assert torch.allclose(penn_midi, torch.tensor(librosa_midi, dtype=torch.float32))
+
+def test_convert_midi_to_frequency():
+    """Test that conversion from MIDI to Hz matches librosa implementation"""
+
+    sample_data = torch.tensor([45.0, 57.0, 69.0, 71.2131, 81.0])   
+
+    penn_frequency = penn.convert.midi_to_frequency(sample_data)
+
+    librosa_frequency = librosa.midi_to_hz(sample_data.numpy())
+
+    assert torch.allclose(penn_frequency, torch.tensor(librosa_frequency, dtype=torch.float32))