Data format when using MediaStream Recording API and streaming ondataavaialble?

[Martin Lundberg]

Hi,

I want to create a small example where I record audio in latest Chrome using the microphone.  I want the audio data to be streamed to a node.js server and streamed to an audio file which I can just download and play in a player. I've read about MediaStream Recording API and I can use the ondataavailable event and event.data to get the data. I can send it to the server using WebSockets but then I'm a little but confused on what format the data that the websocket will retrieve is in? Is it opus codec in a webm container?

Sorry if the question is a little but vague.

-Martin