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POSend audio to Nodejs in a bufferred and efficient way - perhaps with WebRTC
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copied!<p>I would like to accomplish something like this in the browser but plugin-free.</p> <p>It's described in a fully functional Linux command line and in pseudocode:</p> <pre><code>$ arecord -d 5 -f dat -c 1 -f S16_LE -r 8000 |\ speexenc - - |\ curl -X PUT "https://api.example.com/record-sound" -T - </code></pre> <p>Pesudo-code: </p> <ol> <li>Open the mic,</li> <li>Open the connection to the API endpoint</li> <li>Read bytes from the mic on the rate of 8000 Hz (wave pcm signed 16-bit little endian mono 8000 Hz)</li> <li>Encode the bytes to Speex in chunks (<a href="http://speex.org" rel="nofollow">http://speex.org</a>)</li> <li>Write the byte chucks you get from Speex encoder to the webservice request body in chunks - this a lot of bandwidth is saved and bytes are sent as soon as they're available</li> <li>When mic stops giving results (either by a timer <code>-d 5</code> or stopped by the user, flush the request body and <code>send</code> the request.</li> <li>Wait for JSON (or anything else) results in response body</li> </ol> <p>Obviously this is a Linux command line but the algorithm have been successfully applied on: </p> <ol> <li>Linux - using the command above</li> <li>iOS - iPhone and iPad</li> <li>Java2SE on Windows</li> </ol> <p>I would like to achieve the same goal <strong>"efficient and fast streaming from microphone to a server"</strong> on the browser (old browsers are not my concern now). It doesn't have to be a REST server, WebSockets or whatever is possible are as good. Also <strong>Node.js</strong> based solution is prefered.</p> <p>What I have tried so far:</p> <ul> <li>Successfully used a <a href="http://code.google.com/p/flash-videoio/" rel="nofollow">VideoIO.swf</a> which is a Flash based solution and <a href="http://code.google.com/p/rtmplite/" rel="nofollow">RTMPLite</a> on the server to receive video. It's actually a very good solution in terms of functionality except that: <ul> <li>It requires user approval through very bad UI</li> <li>It's not a standard way of doing web and don't allow good error detection and such</li> </ul></li> <li>Successfully used <code>getUserMedia</code> to upload the sound through <a href="https://github.com/mattdiamond/Recorderjs" rel="nofollow">recorder.js</a> and <code>XHR2</code> it works find except that: <ul> <li>It is actually slow because XHR2 needs full data before request can be made using <code>xhr.send(data)</code></li> <li>It is even slower since I could only upload <code>wav</code> format which is way bigger in size compared with <code>ogg</code> and <code>opus</code></li> </ul></li> <li>Researched on the use of WebRTC but couldn't find any resource that mentioned anything other than peer-to-peer connections</li> </ul>

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