Files
voicebox/backend/tests/test_audio_preprocess.py
T
James PineandClaude Opus 4.7 4ffbc03d15 fix(audio): raise trim threshold, cap pad at net-neutral
Review feedback on the preprocessor:

1. ``trim_top_db=30`` was labelled "conservative" in the docstring but is
   actually *more* aggressive than librosa's default of 60. Normal
   speech dynamic range sits around 30 dB, so 30 dB would eat quiet
   trailing syllables and soft consonants. Raise the default to 40 dB —
   below normal speech dynamic range but still catching obvious edge
   silence — and fix the docstring.

2. Unconditional 100 ms edge padding ran even when ``librosa.effects.trim``
   removed nothing. For a well-recorded 29.9 s upload that path would
   push the waveform past the 30 s ceiling and trigger a spurious "too
   long" rejection. Only pad when trimming actually shortened the
   audio, and cap the pad so the output never exceeds the input length.

Adds a regression test for the net-neutral length behaviour.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
2026-04-19 18:25:52 -07:00

113 lines
3.2 KiB
Python

"""
Unit tests for reference-audio preprocessing.
Covers :func:`backend.utils.audio.preprocess_reference_audio` and
:func:`backend.utils.audio.validate_and_load_reference_audio`.
"""
import sys
from pathlib import Path
import numpy as np
import pytest
import soundfile as sf
sys.path.insert(0, str(Path(__file__).parent.parent))
from utils.audio import ( # noqa: E402
preprocess_reference_audio,
validate_and_load_reference_audio,
)
SR = 24000
def _tone(duration_s: float, amp: float = 0.3, freq: float = 220.0) -> np.ndarray:
n = int(duration_s * SR)
t = np.arange(n, dtype=np.float32) / SR
return (amp * np.sin(2 * np.pi * freq * t)).astype(np.float32)
def test_peak_cap_scales_hot_input():
audio = _tone(3.0, amp=0.99)
out = preprocess_reference_audio(audio, SR)
assert np.abs(out).max() <= 0.951
def test_peak_cap_leaves_moderate_input_untouched():
audio = _tone(3.0, amp=0.5)
out = preprocess_reference_audio(audio, SR)
assert np.isclose(np.abs(out).max(), 0.5, atol=1e-3)
def test_dc_offset_removed():
audio = _tone(3.0, amp=0.3) + 0.1
out = preprocess_reference_audio(audio, SR)
assert abs(float(np.mean(out))) < 1e-3
def test_silence_is_trimmed_with_padding_kept():
silence = np.zeros(int(SR * 1.0), dtype=np.float32)
speech = _tone(3.0, amp=0.3)
audio = np.concatenate([silence, speech, silence])
out = preprocess_reference_audio(audio, SR)
# Most of the 2s of leading/trailing silence should be gone, but the
# 3s of speech plus ~200ms of padding should remain.
assert len(audio) - len(out) >= SR, "expected >=1s of silence trimmed"
assert len(out) >= int(3.0 * SR), "speech body should be preserved"
def test_clean_audio_is_not_padded_past_original_length():
# Well-recorded audio with no edge silence shouldn't get longer after
# preprocessing — otherwise a 29.9 s upload could be pushed past the
# 30 s max_duration ceiling downstream.
audio = _tone(3.0, amp=0.3)
out = preprocess_reference_audio(audio, SR)
assert len(out) <= len(audio)
def test_empty_input_returns_empty():
out = preprocess_reference_audio(np.zeros(0, dtype=np.float32), SR)
assert out.size == 0
def test_validate_accepts_previously_rejected_hot_file(tmp_path):
audio = _tone(3.0, amp=0.995)
path = tmp_path / "hot.wav"
sf.write(str(path), audio, SR)
ok, err, out_audio, out_sr = validate_and_load_reference_audio(str(path))
assert ok, f"expected pass, got error: {err}"
assert out_audio is not None
assert out_sr == SR
assert np.abs(out_audio).max() <= 0.951
def test_validate_still_rejects_silent_input(tmp_path):
audio = np.zeros(int(SR * 3.0), dtype=np.float32)
path = tmp_path / "silent.wav"
sf.write(str(path), audio, SR)
ok, err, _, _ = validate_and_load_reference_audio(str(path))
assert not ok
assert err is not None
assert "too short" in err.lower() or "quiet" in err.lower()
def test_validate_rejects_too_short(tmp_path):
audio = _tone(0.5, amp=0.3)
path = tmp_path / "short.wav"
sf.write(str(path), audio, SR)
ok, err, _, _ = validate_and_load_reference_audio(str(path))
assert not ok
assert "too short" in (err or "").lower()
if __name__ == "__main__":
pytest.main([__file__, "-v"])