RE: [tpac] draft minutes from the Web and TV IG f2f meeting at TPAC 2012 (was Re: Notes from today meeting)

Dear Silvia,

A protocol for discovery, and communication between browser does exist inside DLNA guidelines for remote user interface.

Olivier Carmona

-----Original Message-----
From: Silvia Pfeiffer [] 
Sent: mercredi 31 octobre 2012 08:51
To: Giuseppe Pascale
Subject: Re: [tpac] draft minutes from the Web and TV IG f2f meeting at TPAC 2012 (was Re: Notes from today meeting)

On Wed, Oct 31, 2012 at 5:47 PM, Giuseppe Pascale <> wrote:
> On Tue, 30 Oct 2012 10:21:33 +0100, Silvia Pfeiffer 
> <> wrote:
>> Thanks for this - very useful!
> Thanks to you for taking the time to read and comment!
> More in general, during the next months, we will try to collect few 
> use cases and then ping various WGs to get some help to clarify what 
> is already possible and what is not.

Good. I thing it would be helpful to prepare trial implementations of such use cases to be able to pinpoint exactly where the limitations are.

> I'll not go now into the details but only one quick question inline:
>>> Synchronization of Web and TV content
>>>    [52]Sheau's slides
>>>      [52]
>>> on--W3C-TPAC-Oct-29-2012.pptx
>>>    sheau: shows slides
>>>    ... Web&TV Media Synchronization
>>>    ... multiple platform: broadcast, mobile, internet, etc.
>>>    ... hybridization of media
>>>    ... different component media travels over different
>>>    distribution technology
>>>    ... loosely coupled
>>>    ... synchronization between these components is needed
>>>    ... Use cases
>>>    ... single client, multiple client, multi-client dynamically
>>>    switch delivery technology
>>>    ... who initiates the switch?
>>>    ... any mechanism?
>>>    ... Under development
>>>    ... digital fingerprint as ACR (Automatic Content Recognition)
>> About Synchronization: have you see popcorn?
>> They were even on TED recently:
>> Also, are you aware that there are already means to synchronize 
>> separate media elements with each other through the @mediagroup 
>> attribute. That should get you lipsync:
> I believe I mentioned media group (at least offline) but one of the 
> use cases presented by Sheau was to synchronize mediaplayback across 
> different devices in the home, example you are watching a sport event 
> on your main screen and you want alternative camera angles on your 
> tablet, or you are watching a commercial and you want alternative 
> content (still related to the commercial) on your tablet. For some use 
> cases, frame accuracy was required.
> This is something I believe html have no support for. On the other end 
> I'm not sure if html can do anything about this, since this real time 
> synchronization probably needs to be handled by the platform. But 
> maybe there should be a mechanism to initiate/terminate this kind of "real time"
> synchronization from the browser? I'm not sure about the answer, and 
> one of the goal of this group will be to expand on the initial 
> discussion we had on monday and then contact relevant groups to get some feedback.

If you want to synchronize a video timeline between two browsers that run on different devices, you need some kind of communication between these devices. This could go via a server that makes sure the timelines are synchronized, or via a peer-to-peer connection. These are the only two approaches that I know about, but they should get you pretty far.

For example, I published an example in my book [1] where I used a node.js server to synchronize the playback of a video that was provided on a Web Server between all the clients that connected to that video. The node.js server would communicate all "play" and "pause" commands for the video to all peers and thus synchronize the playback. The code is here [2] but it's not working, since the node.js server is not running. You can watch a demo in a recording of an old talk [3].

Anyway - as I said: you should try and implement what you're after using existing technology - you might just find that it's sufficient.



Received on Wednesday, 31 October 2012 15:45:51 UTC