Function _load_audio_ffmpeg

funasr/utils/load_utils.py:318–364

Open an audio file and read as mono waveform, resampling as necessary Parameters ---------- file: str The audio file to open sr: int The sample rate to resample the audio if necessary Returns ------- A NumPy array containing the audio waveform, in

(file: str, sr: int = 16000)

def _load_audio_ffmpeg(file: str, sr: int = 16000):
    """
    Open an audio file and read as mono waveform, resampling as necessary

    Parameters
    ----------
    file: str
        The audio file to open

    sr: int
        The sample rate to resample the audio if necessary

    Returns
    -------
    A NumPy array containing the audio waveform, in float32 dtype.
    """

    # This launches a subprocess to decode audio while down-mixing
    # and resampling as necessary.  Requires the ffmpeg CLI in PATH.
    # fmt: off
    pcm_params = []
    if file.lower().endswith('.pcm'):
        pcm_params = [
            "-f", "s16le",
            "-ar", str(sr),
            "-ac", "1"
        ]

    cmd = [
        "ffmpeg",
        "-nostdin",
        "-threads", "0",
        *pcm_params,  # PCM files need input format specified before -i since PCM is raw data without headers
        "-i", file,
        "-f", "s16le",
        "-ac", "1",
        "-acodec", "pcm_s16le",
        "-ar", str(sr),
        "-"
    ]
    # fmt: on
    try:
        out = run(cmd, capture_output=True, check=True).stdout
    except CalledProcessError as e:
        raise RuntimeError(f"Failed to load audio: {e.stderr.decode()}") from e

    return np.frombuffer(out, np.int16).flatten().astype(np.float32) / 32768.0