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How would I correctly receive/send raw audio data?

I currently receive raw audio data over WebSockets (with Node.js) and write them to a file. Data is sent as byte[] array of 1024 byte in size from a Java client. Audio format is PCM, Mono, 16bit, 44100Hz.

I'm trying to pass on the raw audio data directly to browser, but it doesn't seem to work. What am I missing? Sorry for being new at this. The browsers I tested all support (Webkit) AudioContext. For each package received in browser, I get the following message:

Uncaught SyntaxError: An invalid or illegal string was specified. audio.php:19 1024

Node.js (server):

var WebSocketServer = require('ws').Server
, wss = new WebSocketServer({port: 8081});
var Clients = [];

function findClient(url) {
  return (Clients.indexOf(url));
}

wss.on('connection', function(ws) {

  Clients.push(ws);

  console.log('Connected: %s', ws.upgradeReq.url);
  console.log('Clients: %s', Clients.length);

  ws.on('message', function(message, flags) {

    if(flags.binary) {
      ws.send(message, {binary:true});
    }
    console.log('data arrived: %s', message);
  });

  ws.on('close', function(user) {
    console.log('Disconnected: %s', ws.upgradeReq.url);
    Clients.splice(findClient(ws));
    console.log('Clients: %s', Clients.length);
  });

Client browser:

<script language="javascript">

if (window.webkitAudioContext) {
  var ctx = new webkitAudioContext();
} else if (window.AudioContext) {
  var ctx = new AudioContext();
}

function testSound(buff) {
  var src = ctx.createBufferSource();
  src.buffer = ctx.createBuffer(buff, false);
  //src.looping = false;
  src.connect(ctx.destination);
    src.noteOn(0);
  }
  var ws = new WebSocket('ws://localhost:8081');
  ws.binaryType = 'arraybuffer';
  ws.onmessage = function(e) {
    console.log(e.data.byteLength);
    testSound(e.data);
  }

</script>
Flip
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olealgo
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  • I don't think you can use a buffer source... for this, you are going to have to make a script node. – Brad Nov 28 '13 at 05:33
  • Yeah. Web Audio API buffers are 32-bit floats, from -1 to +1. You're using 16-bit buffers. This method would work if your Arraybuffers were in that format, though. – Kevin Ennis Dec 01 '13 at 21:31
  • Found [this](http://stackoverflow.com/questions/20876152/playing-pcm-stream-from-web-audio-api-on-node-js) question while researching. It seems to have the solution to your question. Linking for convenience. – slamborne Feb 02 '16 at 17:57

0 Answers0