node.js - 将 LINEAR16 音频编码为 Twilio 媒体音频/x-mulaw | Node JS

Question

我一直在尝试将 mulaw 媒体流传输回 Twilio。要求是有效载荷必须是音频/x-mulaw 编码，采样率为 8000 和 base64 编码

我的输入来自@google-cloud/text-to-speech in LINEAR16 Google Docs

我试过了 Wavefile

这就是我对来自@google-cloud/text-to-speech 的响应进行编码的方式

 const wav = new wavefile.WaveFile(speechResponse.audioContent)
    wav.toBitDepth('8')
    wav.toSampleRate(8000)
    wav.toMuLaw()

然后我通过 WebSocket 将结果发送回 Twilio

twilioWebsocket.send(JSON.stringify({
      event: 'media',
      media: {
        payload: wav.toBase64(),
      },
      streamSid: meta.streamSid,
}))

Problem is we only hear random noise on other ends of Twilio call, seems like encoding is not proper

Secondly I have checked the @google-cloud/text-to-speech output audio by saving it in a file and it was proper and clear

Can anyone please help me with the encoding

Answer 1

我也遇到了同样的问题。错误在 wav.toBase64() 中，因为它包含 wav header 。 Twilio 媒体流需要原始音频数据，您可以使用 wav.data.samples 获取这些数据，因此您的代码将是:

 const wav = new wavefile.WaveFile(speechResponse.audioContent)
    wav.toBitDepth('8')
    wav.toSampleRate(8000)
    wav.toMuLaw()

 const payload = Buffer.from(wav.data.samples).toString('base64');