Cannot Publish Custom Audio Frames in Node.js SDK: protoInfo/data_ptr Errors

[ashuitbhu2004]

Describe the bug

I am trying to publish custom audio frames using the Node.js SDK (@livekit/rtc-node), but it is not possible due to internal SDK requirements that cannot be satisfied from userland JavaScript.

Request:
Please provide a supported way to publish custom audio frames from Node.js, or update the documentation to clarify the current limitations.

Reproduction

Steps to Reproduce:

1. Create an AudioSource and attempt to call captureFrame with a plain object or Buffer, as suggested by the documentation.
2. Observe the following error:

• TypeError: frame.protoInfo is not a function

3. Attempt to work around by providing a custom class with a protoInfo() method that returns an object with the expected properties.
4. Observe the following error:

• Error: cannot encode field livekit.proto.AudioFrameBufferInfo.data_ptr to binary: required field not set

Minimal Repro Script:

import { AudioSource } from '@livekit/rtc-node';

// Minimal AudioFrameBufferInfo mimic (plain object)
class AudioFrame {
  constructor({ data, sampleRate, numChannels, samplesPerChannel }) {
    this.data = data;
    this.sampleRate = sampleRate;
    this.numChannels = numChannels;
    this.samplesPerChannel = samplesPerChannel;
  }
  protoInfo() {
    return {
      data: this.data,
      sampleRate: this.sampleRate,
      numChannels: this.numChannels,
      samplesPerChannel: this.samplesPerChannel
    };
  }
}

const audioSource = new AudioSource(48000, 1, 1000);

const frame = new AudioFrame({
  data: Buffer.alloc(480 * 2),
  sampleRate: 48000,
  numChannels: 1,
  samplesPerChannel: 480
});

audioSource.captureFrame(frame);

Logs

Error: cannot encode field livekit.proto.AudioFrameBufferInfo.data_ptr to binary: required field not set

Error stack: TypeError: frame.protoInfo is not a function
    at AudioSource.captureFrame (file:////Voice/node
_modules/@livekit/rtc-node/dist/audio_source.js:89:21)

System Info

Environment:
@livekit/rtc-node version: 0.13.16
Node.js version: 18.20.8
Platform: macOS

Severity

blocking all usage of LiveKit

Additional Information

Analysis:

• The SDK expects a protoInfo() method on the frame object, which is not documented.
• The protobuf encoder expects a data_ptr field, which cannot be set from JavaScript.
• There is no way to create a valid AudioFrameBufferInfo from userland JS, as data_ptr is likely set by native code.

Expected Behavior:

• The SDK should accept a Buffer or plain object for audio frames, as documented, or provide a public API to construct the required protobuf message.