Re: Streaming of WebVTT

On Wed, 25 Jul 2012 16:18:07 +0200, Cyril Concolato  
<cyril.concolato@telecom-paristech.fr> wrote:

> 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,  
> ...)?

Others have answered the real question, but the reason that WebVTT needs a  
header is primarily to disambiguate it from SRT and secondarily to make it  
identifiable without Content-Type.

-- 
Philip Jägenstedt
Core Developer
Opera Software

Received on Thursday, 26 July 2012 09:54:32 UTC