播放正在生成的PCM

Question

I am generating some raw audio data in javascript and I need to play it as I am generating it. I searched for this here and the closest thing to what I am looking for is this . However, in the answer given there the array of data points is generated first and then the audio is played. I need to play it while generating it. Basically I am receiving some stream of some other data, processing it and generating the audio based on that. I need to play the audio corresponding to the data I am receiving as I am receiving it. (A simplified example is receiving the audio volume and frequency.)

Answer 1

If I'm getting the request correctly, then all you need is a ScriptProcessorNode .
You will feed it with your PCM data in the following way:

• wait for its onaudioprocess event.
• get the outputBuffer from the event which is an AudioBuffer .
• loop through each channels of the outputBuffer (will return an Float32Array).
• loop through all the samples of the outputBuffer's channels data.
• set your own data

 function makeSomeNoise() { var ctx = new AudioContext(); var processor = ctx.createScriptProcessor(4096, 1, 1); processor.onaudioprocess = function(evt) { var outputBuffer = evt.outputBuffer; // Loop through the output channels for (var channel = 0; channel < outputBuffer.numberOfChannels; channel++) { var outputData = outputBuffer.getChannelData(channel); // Loop through the 4096 samples for (var sample = 0; sample < outputBuffer.length; sample++) { outputData[sample] = ((Math.random() * 2) - 1) * 0.5; } } }; processor.connect(ctx.destination); } btn.onclick = function() { if (confirm("That won't be really nice")) makeSomeNoise(); } 

 <button id="btn">make some noise</button>