Web Audio API with Bela

luiscript

Hello,

I want use Bela with Node/Web app? I've read at the forum that Bela comes with a version of Node. I'm looking forward to run a web app in order to use the Web Audio API, particularly I want to use the Tone.js library https://github.com/Tonejs/Tone.js. Is this posible? if yes, can you please provide me some guide on how to do it? Thanks.

LiamDonovan

luiscript it would be possible to use the Web Audio API from node.js on the board to control the audio output of Bela, and I think this would be a very powerful way of writing javascript-based DSP web-apps. However it would require writing a C++ 'back end' application to do the audio processing and a communication layer between node and the application.

I made a start at doing this a while ago, using OSC to communicate between node and C++, and I think I managed to get the basics working, though it was far from completed and would require a lot of work to update it and make it compliant with the web audio standard.

If you're interested I can dig out the code and share it.

giuliomoro

node on the board is running only for the purpose of serving the IDE to the user, so to have a self-contained platform for development, but an instrument/effect processor based on Bela would not require the user to use a browser.

If you were to develop a Web Audio API- based application, the audio processing would actually run in the user's browser and not on the board, therefore the actual latency would be down to your OS and browser. Additionally, there would be no straightforward access to the I/Os provided by Bela, so you would effectively be running a node server on a regular BeagleBone Black to make some sounds in your browser.

luiscript

giuliomoro Thank you for your answer and for helping me clarify what node is doing in this context.

luiscript

LiamDonovan good to hear this and yes I'm interested, maybe I can help with the process. Please let us know what you got when you have the time. Thanks.

sletz

Yes please do ! (here developing Faust : http://faust.grame.fr that can target the WebAudio API by generating asm.js code and wrapping it as a ScriprocessorNode)

LiamDonovan

Ok, I'll take a look when I have the chance.

ScriptProcessorNodes don't work very well with Bela though, the BeagleBone simply does not have the raw power necessary to do DSP in javascript (even with asm.js) , you lose the hard-real time and low-latency of Bela, and you waste a massive amount of processing power just getting the audio in and out of node. I vaguely remember getting it working, but having latencies in the hundreds of milliseconds.