f94f94907d
Covers PitchShifter passthrough, frequency shift direction, output length preservation, semitone clamping. AudioPipeline tests verify pitch property defaults, get/set, clamping, and dequeue integration.
79 lines
2.0 KiB
Python
79 lines
2.0 KiB
Python
"""Tests for PitchShifter."""
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import numpy as np
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from tuimble.modulator import PitchShifter
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SAMPLE_RATE = 48000
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FRAME_SIZE = 960 # 20ms at 48kHz
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def _sine_pcm(freq: float, n_samples: int = FRAME_SIZE) -> bytes:
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"""Generate a single-frequency int16 PCM frame."""
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t = np.arange(n_samples) / SAMPLE_RATE
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samples = (np.sin(2 * np.pi * freq * t) * 16000).astype(np.int16)
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return samples.tobytes()
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def _dominant_freq(pcm: bytes) -> float:
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"""Return the dominant frequency in an int16 PCM buffer."""
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samples = np.frombuffer(pcm, dtype=np.int16).astype(np.float32)
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fft = np.abs(np.fft.rfft(samples))
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freqs = np.fft.rfftfreq(len(samples), 1.0 / SAMPLE_RATE)
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return freqs[np.argmax(fft)]
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def test_zero_semitones_passthrough():
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ps = PitchShifter(SAMPLE_RATE)
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pcm = _sine_pcm(440.0)
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assert ps.process(pcm) == pcm
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def test_pitch_shift_changes_output():
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ps = PitchShifter(SAMPLE_RATE)
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pcm = _sine_pcm(440.0)
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ps.semitones = 3.0
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result = ps.process(pcm)
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assert result != pcm
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def test_output_length_preserved():
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ps = PitchShifter(SAMPLE_RATE)
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pcm = _sine_pcm(440.0)
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ps.semitones = 5.0
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result = ps.process(pcm)
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assert len(result) == len(pcm)
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def test_semitones_clamping():
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ps = PitchShifter()
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ps.semitones = 20.0
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assert ps.semitones == 12.0
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ps.semitones = -20.0
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assert ps.semitones == -12.0
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ps.semitones = 5.0
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assert ps.semitones == 5.0
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def test_empty_input():
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ps = PitchShifter()
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ps.semitones = 3.0
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assert ps.process(b"") == b""
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assert ps.process(b"\x00") == b"\x00"
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def test_pitch_up_frequency_increases():
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ps = PitchShifter(SAMPLE_RATE)
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pcm = _sine_pcm(440.0)
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ps.semitones = 4.0
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result = ps.process(pcm)
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assert _dominant_freq(result) > _dominant_freq(pcm)
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def test_pitch_down_frequency_decreases():
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ps = PitchShifter(SAMPLE_RATE)
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pcm = _sine_pcm(440.0)
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ps.semitones = -4.0
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result = ps.process(pcm)
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assert _dominant_freq(result) < _dominant_freq(pcm)
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