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Re: MediaStreams and Media elements

From: Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com>
Date: Fri, 31 May 2013 16:02:56 +0200
Message-ID: <51A8AD90.3020403@ericsson.com>
To: public-media-capture@w3.org
Maybe we should not spend too much time trying to fully understand the 
resource fetch algo. It is difficult to parse.

Perhaps it would be better if we agreed on how we think it should work 
in this specific case, and then tell the html WG that this is how we 
think it should work and ask if that is in line with what they have 
specced (perhaps asking for clarifications).

I would like it to work the following way:

* If a MediaStream with no tracks is attached to a media element, there 
should be no error events fired (but of course nothing is played - there 
is no content)
* Whenever tracks are added to that MediaStream they are detected by the 
media element (adding them to the Audio/VideoTrackList and firing 
addtrack events).


On 2013-05-31 15:41, Jim Barnett wrote:
> Then what is the applicable  clause?  Do we treat it as a failure to
> fetch any data at all?  If that’s  the case, I think that the same logic
> still applies:
> /If the media data
> <http://www.w3.org/TR/html5/embedded-content-0.html#media-data> cannot
> be fetched at all, due to network errors, causing the user agent to give
> up trying to fetch the resource/
> /If the media data
> <http://www.w3.org/TR/html5/embedded-content-0.html#media-data> can be
> fetched but is found by inspection to be in an unsupported format, or
> can otherwise not be rendered at all/
> /DNS errors, HTTP 4xx and 5xx errors (and equivalents in other
> protocols), and other fatal network errors that occur before the user
> agent has established whether the /current media resource/is usable, as
> well as the file using an unsupported container format, or using
> unsupported codecs for all the data, must cause the user agent to
> execute the following steps:/
> /1.//The user agent should cancel the fetching process./
> /2.//Abort this subalgorithm, returning to the resource selection
> algorithm
> <http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-algorithm>./
> //
> Jim
> *From:*rocallahan@gmail.com [mailto:rocallahan@gmail.com] *On Behalf Of
> *Robert O'Callahan
> *Sent:* Friday, May 31, 2013 9:31 AM
> *To:* Jim Barnett
> *Cc:* Adam Bergkvist; public-media-capture@w3.org
> *Subject:* Re: MediaStreams and Media elements
> I don't think your first quotatoin applies to the case where a resource
> is in a known format but has no playable tracks. Possibly "cannot be
> rendered at all" could be interpreted to include the case of no playable
> tracks, but I don't read it that way.
> Rob
> --
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Received on Friday, 31 May 2013 14:03:20 UTC

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