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[media-source] Move VideoPlaybackQuality object to a separate extension spec

From: ddorwin via GitHub <sysbot+gh@w3.org>
Date: Wed, 27 Apr 2016 18:15:40 +0000
To: public-html-media@w3.org
Message-ID: <issues.opened-151454333-1461780900-sysbot+gh@w3.org>
ddorwin has just created a new issue for 
https://github.com/w3c/media-source:

== Move VideoPlaybackQuality object to a separate extension spec ==
I propose that we remove the [`VideoPlaybackQuality` 
object](http://w3c.github.io/media-source/#idl-def-VideoPlaybackQuality)
 and corresponding `getVideoPlaybackQuality()` 
[extension](http://w3c.github.io/media-source/#htmlvideoelement-extensions)
 to the `HTMLVideoElement` element from v1 to be incubated as a 
separate extension. (Possible outcomes include a separate Playback 
Performance Extensions spec or integration into to HTML 5.x.)

1. Although this functionality may be useful for adaptive streaming 
use cases, it is really an independent extension to `HTMLVideoElement`
 that is orthogonal to MSE [1]. It does not affect the core 
functionality of MSE and should be supported for all source types 
(including `.src=` ).

1. There is some question about the best way to provide information 
about current playback performance to applications. As one example, 
there is not currently a way for applications to observe changes. This
 capability would benefit from broader incubation, including from 
those that did not participate in the MSE & EME TF. If this 
functionality goes to REC along with the rest of MSE, any future 
efforts will need to deprecate part of the MSE spec or build around 
it.

1. One member (`totalFrameDelay`) of this object is already marked At 
Risk.

Moving this functionality out of the MSE spec should actually simplify
 the path to PR and REC by reducing the scope of the spec and removing
 one of the At Risk features.

Note: Moving this functionality to another spec/forum _does not_ 
affect what browsers implement - only the declared maturity level of 
the feature. Implementations that have implemented some or all of it 
may continue to do so, but further incubation and iteration is likely 
before it becomes a Recommendation. Implementation experience will be 
valuable input to that process.

Note: We can temporarily move these sections to a separate page within
 the `media-source` repo to provide an informal reference until we 
identify a new home.

[1] When this was added to MSE, there was no established or 
lightweight mechanism for small specs or extensions to existing specs.
 Since that time, the W3C and even HTML have adopted more iterative 
processes.

Please view or discuss this issue at 
https://github.com/w3c/media-source/issues/69 using your GitHub 
account
Received on Wednesday, 27 April 2016 18:15:42 UTC

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