Browser Calls (WebRTC)

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async function callAgent(agentId) {
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  // 1. Get microphone access
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  const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
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  // 2. Create peer connection
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  const pc = new RTCPeerConnection({
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    iceServers: [{ urls: "stun:stun.l.google.com:19302" }],
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  });
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  // 3. Add audio track
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  stream.getTracks().forEach((track) => pc.addTrack(track, stream));
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  // 4. Handle remote audio
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  const remoteAudio = new Audio();
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  remoteAudio.autoplay = true;
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  pc.ontrack = (event) => {
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    remoteAudio.srcObject = event.streams[0];
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  };
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  // 5. Create and send offer
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  const offer = await pc.createOffer();
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  await pc.setLocalDescription(offer);
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  const response = await fetch(
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    `https://api.voicebip.com/v1/public/try/${agentId}/offer`,
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    {
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      method: "POST",
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      headers: { "Content-Type": "application/json" },
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      body: JSON.stringify({ sdp: offer.sdp, agent_id: agentId }),
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    }
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  );
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  const { sdp, call_id } = await response.json();
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  // 6. Set remote description
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  await pc.setRemoteDescription({ type: "answer", sdp });
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  // Call is now active. The agent will greet the caller via TTS.
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  console.log("Call started:", call_id);
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  // 7. Hang up
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  return {
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    hangup: () => {
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      pc.close();
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      stream.getTracks().forEach((track) => track.stop());
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    },
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    callId: call_id,
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  };
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}

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const audioContext = new AudioContext();
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const analyser = audioContext.createAnalyser();
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const source = audioContext.createMediaStreamSource(stream);
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source.connect(analyser);
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analyser.fftSize = 256;
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const dataArray = new Uint8Array(analyser.frequencyBinCount);
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function draw() {
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  analyser.getByteFrequencyData(dataArray);
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  const average = dataArray.reduce((a, b) => a + b) / dataArray.length;
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  // Use `average` to drive a visual indicator (0-255)
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  requestAnimationFrame(draw);
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}
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draw();

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const es = new EventSource(
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  `https://api.voicebip.com/v1/calls/${callId}/transcript/stream?token=${apiKey}`
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);
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es.onmessage = (event) => {
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  const data = JSON.parse(event.data);
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  if (data.event_type === "call.transcription") {
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    console.log("Transcript:", data.payload.text);
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  }
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};
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// Close when done
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es.close();