W3C home > Mailing lists > Public > public-html@w3.org > March 2011

Re: Change Proposal for ISSUE-147

From: Sam Ruby <rubys@intertwingly.net>
Date: Wed, 16 Mar 2011 23:58:14 -0400
Message-ID: <4D8186D6.1070909@intertwingly.net>
To: Ian Hickson <ian@hixie.ch>
CC: "HTML WG (public-html@w3.org)" <public-html@w3.org>
On 03/16/2011 11:19 PM, Ian Hickson wrote:
> On Thu, 17 Mar 2011, Frank Olivier wrote:
>>
>>>> . Setting playbackRate larger than 1.0 for live video will not work.
>>> Sure it will, so long as the playhead is far enough back that there is
>>> buffered content to play.
>>
>> Sure, but what happens when you play through the buffered content and
>> get to (effectively) a live feed? The author should be able to determine
>> that effective playback rate is now 1.0 in this outcome - and setting to
>>> 1.0 should not work.
>
> The spec already covers this -- it's the same as what happens if you're
> playing at the rate of 1.0 but you're receiving only one second's worth of
> media every two seconds.
>
> If we're agreed that the browsers _should_ support this, why would we make
> it effectively optional? Shouldn't this be a quality-of-implementation
> issue, where browsers try their best to approximate the requested rate and
> some do a better job than others? It would be equivalent to how some
> browsers can render canvas faster than others, or how some browsers render
> text more beautifully than others. We don't say that browsers that don't
> support rendering text well should simply refuse to add Text nodes to the
> DOM, right? Why would we require that browsers decide whether or not they
> can do a good enough job of going at the requested rate and force them to
> change the playbackRate accordingly?
>
> Would reporting the playback quality (e.g. number of frames rendered over
> the past second of playback as a fraction of the number of frames that
> would ideally have been rendered during that same period) be an acceptable
> alternative solution?

If you have something concrete to propose, please do so in the form of a 
Change Proposal by the 18th.

- Sam Ruby
Received on Thursday, 17 March 2011 03:58:50 UTC

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