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Re: Track fragments

From: RaphaŽl Troncy <Raphael.Troncy@cwi.nl>
Date: Tue, 16 Feb 2010 19:29:48 +0100
Message-ID: <4B7AE41C.7040505@cwi.nl>
To: Davy Van Deursen <davy.vandeursen@ugent.be>
CC: "'Silvia Pfeiffer'" <silviapfeiffer1@gmail.com>, "'DENOUAL Franck'" <Franck.Denoual@crf.canon.fr>, public-media-fragment@w3.org
Hi Davy,

> If we decide to add support for addressing multiple tracks, I think this
> should be done based on a list of track names. Note that this is already
> implemented within our NinSuna platform: when using track selection, we
> mostly select more than one track using the 'tracks' selector:
> http://example.org?track='track1' : to address one track
> http://example.org?tracks='track1';'track2' : to address multiple tracks

Why do you use 'tracks' instead of 'track'?
What prevent you to use: #track='track1'&track='track2'?

> Do you mean by 'activating' that the server typically sends all the tracks
> to the UA?

We might consider that in any case, the UA will receive a complete media 
file containing all the tracks and will decide to play (activate) some 
of these tracks specified in the URI.
I see the use case, where a media file contains multiple video tracks, 
has very borderline: how many files out there have such a property?

Serving only a number of tracks would be useful to save bandwidth if the 
video track is not served (e.g. audio + audiovision + subtitle for a 
blind user). But then, we would need a minus operator to tell the server 
... send me this media file except the video track. How to express that?

So the more I think, the more I tend to agree with Silvia that in most 
of the cases, we want to the UA to behave a certain way more than 
complex processing on server side. In particular when the track 
selection into a byte range request becomes a nightmare.
I might be very wrong :-)
My 2c.


RaphaŽl Troncy
EURECOM, Multimedia Communications Department
2229, route des CrÍtes, 06560 Sophia Antipolis, 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 Tuesday, 16 February 2010 22:16:32 UTC

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