Re: [MEDIA_PIPELINE_TF] ISSUE-34: ViewPort-Support

Hi Sylvia,

	(this mail will probably bounce from the list since I'm
not a member), please see below re: SVG, timed text, SMIL etc.

--Original Message--:
>On Wed, Aug 10, 2011 at 9:19 PM, Cyril Concolato
><> wrote:
>> Sylvia,
>> Le 10/08/2011 11:46, Silvia Pfeiffer a écrit :
>>> On Wed, Aug 10, 2011 at 5:22 PM, Cyril Concolato
>>> <>  wrote:
>>>> Hi Sylvia,
>>>> Le 10/08/2011 02:38, Silvia Pfeiffer a écrit :
>>>>> I wonder if instead it might be worth analysing if we can come up with
>>>>> a<track>    kind that allows overlaying hyperlinkable regions onto the
>>>>> video?
>>>> Why wouldn't it be possible to have a track element point to some
>>>> animated
>>>> SVG file?
>>> The<track>  element points to timed text, i.e. to a file that provides
>>> text fragments along the timeline of the video. SVG is not suitable
>>> for that use.
>> The fact that the spec puts a restriction is one aspect. I would be happy to
>> know the rationale for it. But I think such restriction however could be
>> removed. From an implementation point of view, we've done it in GPAC [1], it
>> perfectly makes sense to consider SVG as an additional track to a
>> video/audio media. It can be used for subtitling (yet another format),
>> animated graphics (think about dynamic and synchronized ads, ...), regions
>> of interests (See for example [2]).
>Can you fill the TextTrack object and the cues from a SVG? As long as
>you can make a mapping, it's possible. If the format doesn't fit with
>the elements, then it's an orthogonal concept that won't fit the bill.
>In my understanding, SVG has a complex DOM that goes far beyond what
>TextTrack is capable of representing. So, I think it's too rich a
>format for the feature.

SVG Full has a complex DOM yes, SVG Tiny has a tiny DOM called
the micro-DOM which is implemented by GPAC as well as a number
of vendors and is used in the IPTV space and already deployed
in European countries.

SVG Tiny supports a <video> element and the commercial deployments
use that DOM node to manage the hardware decoder, overlaying the
SVG graphics on top.

SMIL is an integral part of SVG, and so timed internationalized
text fits perfectly into the model.

For an example of sub-titles with language switching, see the
paper here:

For examples of deployed UI using SVG as the format, this
commercial vendor already does it:

And lastly, the Opera browser is a dominant player in this
area and they have support for all the SVG Tiny 1.2 features.

I can't currently think of a W3C recommendation (apart from SMIL)
that manages the synchronization for things like sub-titles.
There are a few working drafts floating around, but this can
be and is deployed today by existing open source and commercial
vendors (and it works).


>Of course you can always throw any format at a HTML element. However,
>if browsers don't support it, you can only deal with it through
>JavaScript - so it's not a standardised feature and not really
>relevant to the W3C.

Received on Thursday, 11 August 2011 00:16:42 UTC