- From: Cyril Concolato <cyril.concolato@telecom-paristech.fr>
- Date: Thu, 11 Aug 2011 22:34:47 +0200
- To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- CC: public-web-and-tv@w3.org
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 ? > 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] > 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" ? Regards, Cyril [1] http://biblio.telecom-paristech.fr/cgi-bin/download.cgi?id=7129 > > Cheers, > Silvia. > > >> >> * A pause-on-exit flag: >> not sure what it means but seems applicable >> >> * A writing direction: when restricted to unidirectional text content, it >> would be applicable but I don't see it in the TextTrackCue object >> (http://www.w3.org/TR/html5/video.html#texttrackcue) >> >> * A size: >> not sure I understand why it's not 2 numbers but it could match the SVG >> width (also not in the interface) >> >> * The text of the cue: >> if the SVG animation contains text, it could be passed, if not, could be an >> empty string (or the content of a<desc> element) if required. >> >> The active flag: applicable >> The display state: applicable >> >> What I'm trying to say is that it seems very restrictive to limit the track >> element to pure text tracks. It disables interesting use cases (synchronized >> graphics overlay) while options to do it are there with SVG, already >> implemented in browsers. >> >>> >>> In my understanding, SVG has a complex DOM that goes far beyond what >>> TextTrack is capable of representing. >> >> I don't get this point. The definition of a TextTrack element should not >> care about the expressiveness of the language used to represent the text >> content as long as this language can be mapped to the TextTrack features: if >> it has graphics or not, if it can do bold/italic or not, if it can do bidi >> text or not ... >> >>> So, I think it's too rich a >>> format for the feature. >> >> "Oh I don't want your color TV, I just need a black-and-white one". >> >>> >>> 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. >> >> SVG is not any format. It's a W3C format. I think it's relevant. >> >> Cyril >> >> -- >> Cyril Concolato >> Maître de Conférences/Associate Professor >> Groupe Multimedia/Multimedia Group >> Telecom ParisTech >> 46 rue Barrault >> 75 013 Paris, France >> http://concolato.wp.institut-telecom.fr/ >> -- Cyril Concolato Maître de Conférences/Associate Professor Groupe Multimedia/Multimedia Group Telecom ParisTech 46 rue Barrault 75 013 Paris, France http://concolato.wp.institut-telecom.fr/
Received on Thursday, 11 August 2011 20:35:22 UTC