Subject: RE: [MMUSIC] And one more SDP-quiz question on protocol IDs

From: [email-masked]
Date: Thu, 29 Apr 2004 15:35:00 +0300

Hi Colin

FLUTE transports "files". Potentially any file formats.

It is likely that some applications (server and client) will be used for homogeneous content where every file is of exactly the same type. (In this case, signalling file content type as the <media>+<fmt> is fine IMHO).

However, we expect that in most cases FLUTE will carry more than one (and sometimes very many) content/file types. So only "application" or "data" media types are generic enough for the bulk of cases. (And then signalling a list of file types would be done otherwise if it is necessary for capability or content selection or purchase - I daren't say more for fear of opening the data model can of worms :)

Apart from the IANA registration status of "data", the choice between "application" and "data" seems open to interpretation according to SDP (my earlier email said about as much as I have to say on why). Any opinions on data vs application vs either?

Cheers, Rod.

> -----Original Message-----
> From: ext Colin Perkins [mailto:[email-masked]]
> Sent: Thursday, April 29, 2004 3:09 PM
> To: Walsh Rod (Nokia-NRC/Tampere)
> Cc: [email-masked]; [email-masked]
> Subject: Re: [MMUSIC] And one more SDP-quiz question on protocol IDs
> 
> 
> 
> Rod,
> 
> Can you remind us, briefly, what sort of data is conveyed in a FLUTE 
> session? If it's always a single data format, could we not simply 
> mandate that the MIME type and sub-type are signalled in the SDP "m=" 
> line as the <media> and <fmt> respectively?
> 
> Colin
> 
...

_______________________________________________
mmusic mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/mmusic

---

From: Colin Perkins <[email-masked]>
Date: Thu, 29 Apr 2004 13:41:30 +0100

Hi,

On 29 Apr 2004, at 13:35, <[email-masked]> wrote:
> It is likely that some applications (server and client) will be used 
> for homogeneous content where every file is of exactly the same type. 
> (In this case, signalling file content type as the <media>+<fmt> is 
> fine IMHO).

Okay.

> However, we expect that in most cases FLUTE will carry more than one 
> (and sometimes very many) content/file types. So only "application" or 
> "data" media types are generic enough for the bulk of cases. (And then 
> signalling a list of file types would be done otherwise if it is 
> necessary for capability or content selection or purchase - I daren't 
> say more for fear of opening the data model can of worms :)

How does the receiver know the contents of the FLUTE session if more 
than one file type is transported? Are you trying to signal that list 
in SDP? Or is it picked up from the FLUTE session somehow?

-- 
Colin Perkins
http://csperkins.org/

---

From: Magnus Westerlund <[email-masked]>
Date: Thu, 29 Apr 2004 15:04:09 +0200

Hi,

After having thought of this, what I think for FLUTE is that it actually 
defines its own registry for applications. There will be need for 
different applications to be identified. So if someone is announcing a 
FLUTE delivery session one can also instantiate the correct receiver 
behaviour. Different applications may also go as far as redefining what 
it expects the FDT to contain.

So I think one should consider making definition of how the format 
specific part of the M line should be used. In that one can also 
consider if FLUTE is always one type of media, or if the it really is 
necessary to identify the media type already in the SDP. In my view I 
think we can consider any instantiation of the FLUTE delivery to be for 
the purpose of an application. Therefore use the "application" media 
type. Then the application itself is identified in the FMT part of the 
m= line. A registry for applications is then established so that one can 
determine the application. And it is the applications that defines what 
type of files are actually sent within the FLUTE delivery session.

How does that sound?

Cheers

Magnus

Colin Perkins wrote:

> than one file type is transported? Are you trying to signal that list in 
> SDP? Or is it picked up from the FLUTE session somehow?
> 

-- 

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
----------------------------------------------------------------------
Ericsson AB                | Phone +46 8 4048287
Torshamsgatan 23           | Fax   +46 8 7575550
S-164 80 Stockholm, Sweden | mailto: [email-masked]