Query on MediaRecorder

Hi,

I was going through the MediaRecorder draft in below link.

Link: *http://www.w3.org/TR/2013/WD-mediastream-recording-20130205/*

I have a few queries with this draft.

1) What type of data will get in ondataavailable either encoded audio or
video or both?

2) What is the role of mimeType here?

3) Can u tel me the use case with this data?


Thanks.

Regards,
Dhamodaran