procedural.py 文件源码

def _generate_data(self, num_bytes, offset):
        if self._bytes_per_sample == 1:
            start = offset
            samples = num_bytes
            bias = 127
            amplitude = 127
            data = (ctypes.c_ubyte * samples)()
        else:
            start = offset >> 1
            samples = num_bytes >> 1
            bias = 0
            amplitude = 32767
            data = (ctypes.c_short * samples)()
        self._advance(start)
        ring_buffer = self.ring_buffer
        decay = self.decay
        for i in range(samples):
            data[i] = int(ring_buffer[0] * amplitude + bias)
            ring_buffer.append(decay * (ring_buffer[0] + ring_buffer[1]) / 2)
        return data