RE: What does MediaStreamRecorder.getRecordedData() actually return?

To get data out of a Blob, you can use the FileReader (generally for all Blobs): http://dev.w3.org/2006/webapi/FileAPI/#FileReader-interface

There's no need to sub-class to File to use FileReader to read a blob.


From: cowwoc [mailto:cowwoc@bbs.darktech.org]
Sent: Wednesday, September 11, 2013 1:34 PM
To: Adam Bergkvist
Cc: public-media-capture@w3.org
Subject: Re: What does MediaStreamRecorder.getRecordedData() actually return?

On 11/09/2013 5:57 AM, Adam Bergkvist wrote:
On 2013-09-11 06:54, cowwoc wrote:

Hi,

http://dev.w3.org/2011/webrtc/editor/webrtc-20111004.html#dom-mediastreamrecorder-getrecordeddata
reads:

You're looking at a really old version (2011-10-04) of the spec.

The MediaStream recording stuff has been moved to a dedicated spec [1].

/Adam

[1] https://dvcs.w3.org/hg/dap/raw-file/default/media-stream-capture/MediaRecorder.html

Thanks, but this only answers my last question. The rest of the questions still hold:

  1.  It's not clear (to me at least) whether the data being returned consists of the compressed WebM audio+video (muxed) data or something else. Perhaps the document should be more explicit?
  2.  In the case of the incoming MediaStream I can see the browser having no problem returning a compressed stream, but does this imply that the outgoing MediaStream must compress the audio+video before passing it into the recorder? This implies that localhost recording app (without a remote end) is more expensive than it needs to me. Certainly this is an edge-case, but it's worth considering.
    Looking at https://dvcs.w3.org/hg/dap/raw-file/default/media-stream-capture/MediaRecorder.html#blob-event <https://dvcs.w3.org/hg/dap/raw-file/default/media-stream-capture/MediaRecorder.html#blob-event>  the API returns a Blob but looking at http://www.w3.org/TR/2009/WD-FileAPI-20091117/#dfn-Blob there is no way to get bytes out of a Blob. I believe the API is supposed to refer to a subclass (e.g. File) which allows us to read the bytes (e.g. using FileReader). Shouldn't the recorder API exposes a sub-class?

Gili