Not able to get transcript when sending audio in webm format

[deva-gopalani]

I have got a web app in which I am collecting the audio of users via mic. On collecting the audio I am extracting the base64 value of the raw audio and sending it over a websocket connection to my backend. The code responsible for doing all this is -

navigator.mediaDevices
  .getUserMedia({ audio: true })
  .then((stream) => {
    const url = "<wss-endpoint-to-my-server>"
    const ws = new WebSocket(url)
    
    ws.onopen = () => {
      console.log('WebSocket connected.')
    }

    const options = { mimeType: 'audio/webm;' }
    const mediaRecorder = new MediaRecorder(stream, options)

    mediaRecorder.ondataavailable = (event) => {
      const audioBlob = event.data
      const reader = new FileReader()

      reader.onloadend = () => {
        if (ws.readyState != WebSocket.OPEN) {
          return
        }
        let audioMessage = reader.result
        // extracting base64 string
        audioMessage = audioMessage.split(',')[1]

        // sending to my server
        ws.send(JSON.stringify({ type: 'audio', data: audioMessage }))
      }
      reader.readAsDataURL(audioBlob)
    }
    mediaRecorder.start(200)
  })
  .catch((error) => {
    console.error('Error accessing microphone:', error)
  })

Once I receive this audio in the backend, I decode it and then send it to deepgram for transcription. Now the issue is that I am not able to get any transcription. What could be the possible reason for it? The code present in the backend is as follows -

# Here audio is the base64 string sent from the frontend
data = base64.b64decode(audio)
deepgram_websocket.send(data)

The URL with which I created the websocket connection with deepgram is as follows -
wss://api.deepgram.com/v1/listen?model=nova-2&filler_words=true&diarize=true&language=en&vad_events=true&encoding=opus&sample_rate=48000&channels=1&interim_results=true&utterance_end_ms=1000

I have specified the encoding as opus as the browser is giving me the audio in webm format and the sample rate of it is 48KHz hence the sample rate has been set to the same.

What could be the possible reason for this to not work? If you have any other better recommended approach to make this flow work then also do let me know.

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[deepgram-community[bot]]

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• The deepgram product you are using (e.g Speech to Text, Agent API)
• A request ID that triggered your error or issue.

[deva-gopalani]

@jkroll-deepgram @jpvajda any sort of assistance would be highly appreciated!