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Re: Media Fragments - Video fragment temporal loop

From: RaphaŽl Troncy <raphael.troncy@eurecom.fr>
Date: Thu, 27 Feb 2014 16:53:07 +0100
Message-ID: <530F5F63.7060507@eurecom.fr>
To: Philip Jšgenstedt <philipj@opera.com>, Silvia Pfeiffer <silviapfeiffer1@gmail.com>
CC: Leeroy <soupress@gmail.com>, Media Fragment <public-media-fragment@w3.org>
> To make it loop exactly between the start time and the end time you
> have to integrate with the media framework, otherwise the looping
> won't be gapless and it won't loop exactly the same number of samples
> each time.

Let's consider the case <video src="holidays.webm#t=320,960" loop>. The 
first playback might starts at second 319,56 and ends at 960,14 because 
you look for the closest I frame. When looping, you will have exactly 
the same behavior.

> An implementation that doesn't loop accurately doesn't add
> anything that you can't do by seeking in JavaScript at the appropriate
> time.

Yes, you can seek in javascript. The use case here is different: you 
might want to share a media fragment URI and just expect your client to 
play this fragment (starting at start fragment time and pausing at end 
fragment time).

> I suspect that implementors will say "just use Web Audio API" if
> asked to implement accurate looping for <audio src="sound#t=1,2"
> loop>.

What about <video>? And let's not looking at corner cases such as 
#t=1,2. People are sharing *real* fragments!
Best regards.


RaphaŽl Troncy
EURECOM, Campus SophiaTech
Multimedia Communications Department
450 route des Chappes, 06410 Biot, France.
e-mail: raphael.troncy@eurecom.fr & raphael.troncy@gmail.com
Tel: +33 (0)4 - 9300 8242
Fax: +33 (0)4 - 9000 8200
Web: http://www.eurecom.fr/~troncy/
Received on Thursday, 27 February 2014 15:53:42 UTC

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