Streaming of WebVTT

Hi all,

I'm trying to integrate WebVTT content in streaming context (MP4, RTP, 
DASH, MPEG-2 ...) in general. Aside from the problem of random access 
points that I mentionned in my previous email [1], there is a problem 
with the fact that the "WEBVTT" string has to be at the beginning of the 
file. Consider the following case, I have a live event and I want client 
to connect to an HTTP-delivered WebVTT resource, I'd like to update that 
resource from time to time (removing old cues, adjusting times and 
adding new cues) and enable both clients already connected to get the 
update and for new clients to get the new content. That same file has to 
have the "WEBVTT" string for new clients, but cannot be used as is for 
the already connected client (I'll have to strip off the "WEBVTT" 
string). What is the use of that string? Is it really needed given that 
many resources on the web don't use magic numbers (HTML, XML, SRT, SVG, 
...)?

Thanks,
Cyril
[1] http://lists.w3.org/Archives/Public/public-texttracks/2012Jul/0000.html

-- 
Cyril Concolato
Maître de Conférences/Associate Professor
Groupe Multimedia/Multimedia Group
Telecom ParisTech
46 rue Barrault
75 013 Paris, France
http://concolato.wp.mines-telecom.fr/

Received on Wednesday, 25 July 2012 14:18:45 UTC