ReactJS + WebSocket + Vosk

[fkurushin]

I writes react client to recognise speech through web sockets. I am happily connected to the server (alphacep/kaldi-ru:latest), send requests there, everything alright, but my responses is empty. Can anyone please take a look at my code?

import React, { useRef, useEffect, useState } from 'react';

const URL = 'ws://localhost:2700';
const sampleRate = 16000;
const blockSize = 4000;
const dt = blockSize / sampleRate * 1000;

const SpeechRecoPage = () => {
  const [isRecording, setIsRecording] = useState(false);
  const [mediaRecorder, setMediaRecorder] = useState(null);
  const socket = useRef(null);

  useEffect(() => {
    if (!socket.current) {
      socket.current = new WebSocket(URL);
    };

    socket.current.onopen = function () {
      socket.current.send(JSON.stringify({ config: { sample_rate: sampleRate } }));
      console.log('Connection established');
    };

    socket.current.onmessage = function (event) {
      console.log(`Received message: ${event.data}`);
    };

    socket.current.onclose = function (event) {
      console.log(`Connection closed: ${event.code} ${event.reason}`);
    };

    socket.current.onerror = function (event) {
      console.error('WebSocket error observed:', event);
    };

    setIsRecording(true);
    navigator.mediaDevices
      .getUserMedia({
        video: false,
        audio: {
            echoCancellation: true,
            noiseSuppression: true,
            channelCount: 1,
            sampleRate: sampleRate,

        },
    }).then((stream) => {
        const mediaRecorder = new MediaRecorder(stream);
        mediaRecorder.start(dt)
        setMediaRecorder(mediaRecorder);
        mediaRecorder.addEventListener('dataavailable', (event) => {
          if (socket.current.readyState === WebSocket.OPEN) {
            console.log(event.data)
            socket.current.send(event.data);
          }
        });
        // mediaRecorder.start();
      })
      .catch((error) => {
        console.log(`Error accessing microphone: ${error.message}`);
      });

  }, []);

  const closeConnection = () => {
    setIsRecording(false);
    mediaRecorder.stop();
    if (socket.current.readyState === WebSocket.OPEN) {
      socket.current.send('{"eof" : 1}')
    }
  };

  return (
    <div>
      <h1>RECORDING</h1>
      {isRecording ? (
        <button onClick={closeConnection}>Stop Recording</button>
      ) : (
        <button onClick={setIsRecording(true)}>Start Recording</button>
      )}
    </div>
  );
};

export default SpeechRecoPage;

This is client logs:

Any help welcome, thank you!

[nshmyrev]

You try to send mp4 to websocket while it expects raw wav. You need to modify server to handle mp4.

We use AudioContext worklet to record audio instead, you can find example here:

https://github.com/alphacep/vosk-server/tree/master/client-samples/javascript

Overall, we recommend webrtc server for web, not websockets, it is more appropriate approach:

https://github.com/alphacep/vosk-server/tree/master/webrtc

[fkurushin]

Hi @nshmyrev thank you for the answer. I thought that if server passed the process_chunk without errors it accepts my request.

def process_chunk(rec, message):
    if message == '{"eof" : 1}':
        return rec.FinalResult(), True
    if message == '{"reset" : 1}':
        return rec.FinalResult(), False
    elif rec.AcceptWaveform(message):
        return rec.Result(), False
    else:
        return rec.PartialResult(), False

Overall, I will try to convert to audio/wav, than audio context, and webrtc.