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import os
from typing import BinaryIO
import ffmpeg
import numpy as np
SAMPLE_RATE = 16000
FFMPEG_BIN = os.getenv("FFMPEG_BIN", "ffmpeg")
def load_audio(file: BinaryIO, encode=True, sr: int = SAMPLE_RATE):
"""
Open an audio file object and read as mono waveform, resampling as necessary.
Modified from https://github.com/openai/whisper/blob/main/whisper/audio.py to accept a file object
Parameters
----------
file: BinaryIO
The audio file like object
encode: Boolean
If true, encode audio stream to WAV before sending to whisper
sr: int
The sample rate to resample the audio if necessary
Returns
-------
A NumPy array containing the audio waveform, in float32 dtype.
"""
if encode:
try:
# This launches a subprocess to decode audio while down-mixing and resampling as necessary.
# Requires the ffmpeg CLI and `ffmpeg-python` package to be installed.
out, _ = (
ffmpeg.input("pipe:", threads=0)
.output("-", format="s16le", acodec="pcm_s16le", ac=1, ar=sr)
.run(cmd=FFMPEG_BIN, capture_stdout=True, capture_stderr=True, input=file.read())
)
except ffmpeg.Error as e:
raise RuntimeError(f"Failed to load audio: {e.stderr.decode()}") from e
else:
out = file.read()
try:
return np.frombuffer(out, np.int16).flatten().astype(np.float32) / 32768.0
except Exception as e:
# TODO: Unsupported file formats can raise the following exception:
# ValueError: buffer size must be a multiple of element size
# This should be made more robust.
raise RuntimeError("Failed to load audio") from e