Re: Tech Discussions on the Multitrack Media (issue-152)

On Thu, 17 Feb 2011 18:43:49 +0100, Mark Watson <>  

> On Feb 17, 2011, at 7:17 AM, Philip Jägenstedt wrote:
>> On Wed, 16 Feb 2011 18:47:22 +0100, Mark Watson <>
>> wrote:
>>> On Feb 16, 2011, at 12:02 AM, Philip Jägenstedt wrote:
>>>> On Wed, 16 Feb 2011 03:31:47 +0100, Silvia Pfeiffer
>>>> <> wrote:
>>>>> On Wed, Feb 16, 2011 at 12:08 PM, Jonas Sicking <>
>>>>> wrote:
>>>>>> On Tue, Feb 15, 2011 at 4:19 PM, Silvia Pfeiffer
>>>>>> <> wrote:
>>>>>>> On Wed, Feb 16, 2011 at 5:36 AM, Mark Watson <>
>>>>>>> wrote:
>>>>>>>> Hi Philip,
>>>>>>>> Just a quick note that the "alternative" vs "additional"  
>>>>>>>> distinction
>>>>>>>> is not always completely clear. Video with different camera angles
>>>>>>>> (gimmiky or not) could be considered as an alternative, or could  
>>>>>>>> be
>>>>>>>> rendered as picture-in-picture, or multiple thumbnail videos could
>>>>>>>> show beside the main video (some sports sites already do this kind
>>>>>>>> of
>>>>>>>> thing).
>>>> Sure, but all of those modes should be achieved by the author making  
>>>> it
>>>> happen with CSS. At the risk of making a strawman argument, I honestly
>>>> can't see browsers allowing the user to change the rendering of the  
>>>> page
>>>> to achieve PiP or something like that when the author hasn't provided
>>>> for
>>>> it, messing with the layout like that seems both weird and unlikely to
>>>> be
>>>> useful. Of course we can have User JavaScript and User CSS to do that
>>>> kind
>>>> of thing, though.
>>> I was assuming that the "author" of the content - who labels the tracks
>>> - might not be the same as the "author" of the webpage that is  
>>> rendering
>>> the content. So the first author should not assume that (say) multiple
>>> views are alternatives, because some webpages might be able to view  
>>> them
>>> both as PIP.
>> Since the tracks are labeled using the attribute of the <track>  
>> attribute,
>> it will be the page author that has to do the work to support some
>> specific video display, be that PiP, overlay or something else.
> That would be the case for track objects created as a result of <track>  
> elements, but what about in-band tracks ? The page author does the work  
> for PIP etc., of course, but the media author should not assume that  
> such capabilities are or are not available on the pages where their  
> media might be used: they should just label the tracks and let the page  
> to whatever it is capable of.

I don't think we should spend much time making extra in-band video tracks  
work more than barely, if at all, since the extra bandwidth needed to have  
multiple in-band video tracks makes it quite unlikely the feature would be  
used to any greater extent.

If they should work at all, my position is that the only thing you should  
be able to do with in-band video tracks is switch between them, in other  
words what I've called alternative tracks. Either having some kind of  
layout information in the file itself or having HTML markup to target  
individual tracks of the same resource seems like unjustified complexity  
and spec/implementation effort not very well spent.

Philip Jägenstedt
Core Developer
Opera Software

Received on Friday, 18 February 2011 10:08:48 UTC