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[media-source] By HTML 5.1 spec, the mediasource should never be detached from the media element

From: Jean-Yves Avenard via GitHub <sysbot+gh@w3.org>
Date: Thu, 15 Sep 2016 07:22:46 +0000
To: public-html-media@w3.org
Message-ID: <issues.opened-177107211-1473924164-sysbot+gh@w3.org>
jyavenard has just created a new issue for 
https://github.com/w3c/media-source:

== By HTML 5.1 spec, the mediasource should never be detached from the
 media element ==
I lodged a test bug in 
https://github.com/w3c/web-platform-tests/issues/3726

However, I do believe that we have a problem in the MSE specs 
themselves.

According to the spec, we are to detach the mediasource from the media
 element when the element's networkState moves to NETWORK_EMPTY
(ref: 
https://w3c.github.io/media-source/index.html#mediasource-detach)

However, following the HTML spec, we will never transition to 
NETWORK_EMPTY with mediasource, as the only time this can occur is 

"⌛ Otherwise the media element has no assigned media provider object 
and has neither a src attribute nor a source element child: set the 
networkState to NETWORK_EMPTY, and abort these steps; the synchronous 
section ends."
https://html.spec.whatwg.org/multipage/embedded-content.html#concept-media-load-algorithm

or "If the media data fetching process is aborted by the user".

And if an error occurs during the resource selection algorithm, then 
we are to run 

"The dedicated media source failure steps with a list of promises 
promises are the following steps:
    1. Set the error attribute to a new MediaError object whose code 
attribute is set to MEDIA_ERR_SRC_NOT_SUPPORTED.
    2. Forget the media element's media-resource-specific tracks.
    3. Set the element's networkState attribute to the 
NETWORK_NO_SOURCE value.
    4. Set the element's show poster flag to true.
    5. Fire a simple event named error at the media element.
    6. Reject pending play promises with promises and a 
"NotSupportedError" DOMException.
    7. Set the element's delaying-the-load-event flag to false. This 
stops delaying the load event.
"

so here networkState goes to NETWORK_NO_SOURCE

So I'm puzzled on what the proper course of action should be or the 
wording...

Please view or discuss this issue at 
https://github.com/w3c/media-source/issues/162 using your GitHub 
account
Received on Thursday, 15 September 2016 07:23:00 UTC

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