它似乎是逐个样本交错的,左通道在前。当左声道输入有信号且右声道输入静音时,我得到:
result = [0.2776, -0.0002, 0.2732, -0.0002, 0.2688, -0.0001, 0.2643, -0.0003, 0.2599, ...
因此,要将其分离为立体声流,请重新整形为 2D 数组:
result = np.fromstring(in_data, dtype=np.float32)
result = np.reshape(result, (frames_per_buffer, 2))
现在要访问左通道,请使用result[:, 0]
,对于右通道,使用result[:, 1]
.
def decode(in_data, channels):
"""
Convert a byte stream into a 2D numpy array with
shape (chunk_size, channels)
Samples are interleaved, so for a stereo stream with left channel
of [L0, L1, L2, ...] and right channel of [R0, R1, R2, ...], the output
is ordered as [L0, R0, L1, R1, ...]
"""
# TODO: handle data type as parameter, convert between pyaudio/numpy types
result = np.fromstring(in_data, dtype=np.float32)
chunk_length = len(result) / channels
assert chunk_length == int(chunk_length)
result = np.reshape(result, (chunk_length, channels))
return result
def encode(signal):
"""
Convert a 2D numpy array into a byte stream for PyAudio
Signal should be a numpy array with shape (chunk_size, channels)
"""
interleaved = signal.flatten()
# TODO: handle data type as parameter, convert between pyaudio/numpy types
out_data = interleaved.astype(np.float32).tostring()
return out_data