在python上使用百度语音的语音识别总是返回3301，录音结束之后无法识别，提示3301，但是单独把文件拿出来试听，个人感觉比示例文件清晰

代码：

speech = base64.b64encode(signal).decode("utf-8")
mac_address = uuid.UUID(int=uuid.getnode()).hex[-12:]
rate = rate
data = {
"format": "pcm",
"lan": "zh",
"token": token,
"len": speech_length,
"rate": rate,
"speech": speech,
"cuid": mac_address,
"channel": 1,

}

错误信息：{'err_msg': 'speech quality error.', 'err_no': 3301, 'sn': '539323464501555052950'}