backend/audio_utils.py

from __future__ import annotations
import numpy as np
import config

def truncate_or_left_pad(audio: np.ndarray, n_seconds: int=config.SMART_TURN_WINDOW_SECONDS, sample_rate: int=config.SAMPLE_RATE) -> np.ndarray:
    audio = np.asarray(audio, dtype=np.float32)
    max_samples = n_seconds * sample_rate
    if len(audio) > max_samples:
        return audio[-max_samples:]
    if len(audio) < max_samples:
        padding = max_samples - len(audio)
        return np.pad(audio, (padding, 0), mode='constant', constant_values=0)
    return audio