RE: [HOME_NETWORK_TF] Home Network Technologies

Hi Matt,

 

Let me try to answer "frame" your question/observation and hopefully provide some brief answers:

 

Q1: Does DLNA/UPnP distinguish between the description of content, i.e. metadata describing content (title, description, available media formats) and the device actually supplying the content?

 

Q2: Does DLNA/UPnP allow metadata and content to reside on separate devices on the home network?

 

Q3: Does DLNA/UPnP allow the remote commanding of playback devices?

 

 

A1: Yes...DLNA/UPnP has a distinct metadata service (ContentDirectory Service). The metadata provided by this service can refer to content elsewhere on the home network.

 

A2: Yes

 

A3: Yes...UPnP/DLNA allows remote commanding of playback devices. A Digital Media Controller can obtain descriptive content metadata and tell a playback device to "pull" a piece of content from a distinct "content source" on the home network. 

 

The Digital Media Controller in this scenario would examine the metadata from both the Playback Device (Digital Media Renderer) and from the metadata service (Digital Media Server - ContentDirectory Service) and insure a media format is chosen that both the Content Source can provide and the Playback Device can render. Once a match is found the Digital Media Controller, would command the Playback device to fetch the content from the Content Source.

 

Regards,

Russell Berkoff

Samsung Electronics

 

 

 

-----Original Message-----
From: Matt Hammond [mailto:matt.hammond@rd.bbc.co.uk] 
Sent: Wednesday, April 06, 2011 5:03 AM
To: public-web-and-tv@w3.org; Olivier Carmona
Cc: Russell Berkoff; Giuseppe Pascale
Subject: Re: [HOME_NETWORK_TF] Home Network Technologies

 

Hi Olivier,

 

On Wed, 06 Apr 2011 12:22:38 +0100, Olivier Carmona <ocarmona@awox.com>  

wrote:

 

> 

> Hi Matt,

> 

> DLNA 1.0 is about two-box pull model: on one side you have a Digital  

> Media Player (a client in your description) and on the other side you  

> have a Digital Media Server (a rendering device in your description).  

> DMP discovers and then browses DMS, and can request one of the browsed  

> items to be played. The only difference with your model is that this the  

> DMP that based on the information exposed by the DMS, decides wherever  

> it can play the content.

 

My explanation was not as clear as it should have been - please accept my  

apologies for that. The client that I described does not display media and  

does not send or receive media streams. It is the server that will  

render/display media, and it is up to the server to work out what media is  

available to it and to arrange to stream (or otherwise obtain) it. This  

aspect would be completely opaque to this client. The server/renderer  

could well use DLNA to discover and stream that content from a 3rd device,  

but the client would not be aware of this.

 

For me, the attraction of this model is that it is more abstract that just  

streaming and can easily subsume access to local storage but also access  

to services such as live television broadcast. A television programme is  

just another item of content that the server reports it has available to  

it, and which the client can ask it to display.

 

 

 

regards

 

 

Matt

-- 

| Matt Hammond

| Research Engineer, BBC R&D, Centre House, London

| http://www.bbc.co.uk/rd/