IBM Watson：Text-to-Spech Wave 编解码器

如何解决IBM Watson：Text-to-Spech Wave 编解码器

我正在尝试在 ITU G.711 mu-law、单声道 8 khz 格式上创建 WAV，但它们无声：

def text_to_speach(text,audio_voice,output_file):
    """
    Converts Text to speach using IBM Watson
    """    
   
    apikey = <mykey>

    url = <myURL>

    # Setup Service
    authenticator = IAMAuthenticator(apikey)
    tts = TextToSpeechV1(authenticator=authenticator)
    tts.set_service_url(url)

    with open(output_file,"wb") as audio_file:
        res = tts.synthesize(text,accept="audio/mulaw;rate=8000",voice=audio_voice).get_result()

        audio_file.write(res.content)

    print("Done!!!")

请指教。