95 lines
2.7 KiB
Python
95 lines
2.7 KiB
Python
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"""Audio helpers for the voice pipeline.
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Wire format everywhere: SLIN — signed 16-bit LE mono PCM @ 8 kHz (AudioSocket).
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Whisper wants 16 kHz; TTS providers are asked for 8 kHz where possible and
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resampled otherwise.
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"""
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from __future__ import annotations
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import audioop
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import io
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import math
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import wave
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SAMPLE_RATE = 8000
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SAMPLE_WIDTH = 2 # bytes, 16-bit
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FRAME_MS = 20
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FRAME_BYTES = SAMPLE_RATE * SAMPLE_WIDTH * FRAME_MS // 1000 # 320
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def resample(pcm: bytes, from_rate: int, to_rate: int) -> bytes:
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if from_rate == to_rate or not pcm:
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return pcm
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out, _ = audioop.ratecv(pcm, SAMPLE_WIDTH, 1, from_rate, to_rate, None)
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return out
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def rms(pcm: bytes) -> int:
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return audioop.rms(pcm, SAMPLE_WIDTH) if pcm else 0
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def duration_s(pcm: bytes, rate: int = SAMPLE_RATE) -> float:
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return len(pcm) / (rate * SAMPLE_WIDTH)
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def silence(ms: int, rate: int = SAMPLE_RATE) -> bytes:
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return b"\x00" * (rate * SAMPLE_WIDTH * ms // 1000)
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def tone(freq: int, ms: int, rate: int = SAMPLE_RATE, amplitude: int = 12000) -> bytes:
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"""Test helper: sine tone (registers as speech for the energy VAD)."""
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n = rate * ms // 1000
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return b"".join(
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int(amplitude * math.sin(2 * math.pi * freq * i / rate)).to_bytes(
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2, "little", signed=True
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)
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for i in range(n)
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)
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def pcm_to_wav(pcm: bytes, rate: int = SAMPLE_RATE) -> bytes:
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buf = io.BytesIO()
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with wave.open(buf, "wb") as w:
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w.setnchannels(1)
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w.setsampwidth(SAMPLE_WIDTH)
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w.setframerate(rate)
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w.writeframes(pcm)
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return buf.getvalue()
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def mix(a: bytes, b: bytes) -> bytes:
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"""Mix two PCM streams (unequal lengths ok)."""
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if len(a) < len(b):
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a, b = b, a
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if not b:
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return a
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mixed = audioop.add(a[: len(b)], b, SAMPLE_WIDTH)
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return mixed + a[len(b):]
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class CallRecorder:
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"""Accumulates caller + agent audio on a shared timeline and writes a WAV."""
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def __init__(self) -> None:
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self._caller = bytearray()
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self._agent = bytearray()
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def add_caller(self, pcm: bytes) -> None:
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self._caller.extend(pcm)
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# keep agent track in sync (silence while caller talks)
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if len(self._agent) < len(self._caller):
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self._agent.extend(b"\x00" * (len(self._caller) - len(self._agent)))
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def add_agent(self, pcm: bytes) -> None:
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self._agent.extend(pcm)
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if len(self._caller) < len(self._agent):
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self._caller.extend(b"\x00" * (len(self._agent) - len(self._caller)))
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def to_wav(self) -> bytes:
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return pcm_to_wav(mix(bytes(self._caller), bytes(self._agent)))
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@property
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def seconds(self) -> float:
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return duration_s(bytes(self._caller))
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