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

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Fri, 12 Aug 2011 07:31:03 +1000
Message-ID: <CAHp8n2m2bLarapyU-ZaQAwuxWdJE0ks3K8BfPv0sBH-kLj0-rA@mail.gmail.com>
To: Cyril Concolato <cyril.concolato@telecom-paristech.fr>
Cc: public-web-and-tv@w3.org
On Fri, Aug 12, 2011 at 6:34 AM, Cyril Concolato
<cyril.concolato@telecom-paristech.fr> wrote:
> Le 11/08/2011 12:34, Silvia Pfeiffer a écrit :
>>
>> On Thu, Aug 11, 2011 at 7:35 PM, Cyril Concolato
>> <cyril.concolato@telecom-paristech.fr>  wrote:
>>>
>>> Hi Sylvia,
>>>
>>>> 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.
>>>
>>> Reading http://www.w3.org/TR/html5/video.html#text-track it says:
>>> "A text track consists of:"
>>> * "The kind of text track": would apply to SVG tracks
>>> * "A label": would apply to SVG tracks
>>> * "A language": would apply to SVG tracks
>>> * "A readiness state": would apply as well
>>> * "A mode": same
>>> * "A list of zero or more cues"
>>>
>>> A Cue is defined as:
>>> * "An identifier": applicable to SVG tracks
>>>
>>> * "A start time"/"An end time":
>>> As such SVG does not define frame-based content as Flash would do or
>>> other
>>> subtitling formats, but you can define frame-based content such as:
>>> http://perso.telecom-paristech.fr/~concolat/SVG/flash8.svg
>>
>> This is one of the major requirements.
>
> Do you have a document describing those requirements ?

The HTML specification incorporates these requirements.


>> Trust me - SVG won't fit the
>> bill as a time-aligned data format.
>
> General purpose SVG no but SVG with some constraints yes. It's not the
> perfect time-aligned format but it works. I've demonstrated that it's
> possible to fragment some SVG into frames, store them in MP4, stream them
> ... [1]

Right. That's why it's not generally useful for the <track> purpose.
You could define a sub-language (like a profile) of SVG that might
fit, but then it's not SVG any more.


>> And browsers won't implement it.
>
> That me be true for now but you never know. They might be interested in it.
>
>> But you can always try a JavaScript implementation to prove me wrong.
>
> "implementation of what" ?

A demonstration of how SVG in <track> is useful. You can always extend
the HTML functionality through JavaScript to demonstrate such things
and make a point towards including it into HTML. That's in fact the
best approach to getting new features happening. Just as you've shown
SVG in MP4, you should demonstrate SVG in <track> if that is what you
want to achieve.

Cheers,
Silvia.
Received on Thursday, 11 August 2011 21:32:00 UTC

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