Subject: Re: contributions to MPEG on 4onIP

From: Colin Perkins <[email-masked]>
Date: Tue, 01 Aug 2000 17:56:47 -0400

Coming back to this rather late, apologies....

--> CURET Dominique FTRD/DMI/REN writes:
>dear Colin, dear all,
>
>As Colin suggested to me, as most of the IETF folks dnot belong to MPEG
>and as only a good collaboration between us will bring palatable
>standards,
>
>Here are two zipped MPEG contributions to which I participated, on the way
>to declare MPEG signals carriage over RTP in the SDP syntax.
>
>One contribution (m6169) is an update of the work initialised by MPEG at
>the last Geneva meeting (MPEG document N3381): " a framework for the
>delivery of MPEG-4 over IP based protocols".  That N3381 document is also
>describing quickly a possible SDP solution.
>
>The second contribution (m6162), is not at all a framework, it is only
>focussed on a modification of the SDP syntax. This syntax being more
>widely studied.

A couple of comments:
- typical use of SDP is for media specific parameters to be signalled in an
  a=fmtp attribute, rather than as parameters to a=rtpmap. This affects
  section 3.1.3 of your document.

- in section 3.2.2 you have to be a little careful, since a=rtpmap
  references a name in the MIME namespace. So any definition here will need
  a MIME registration. e.g. you have defined the MIME type audio/x-mpeg4-es
  here, perhaps. (same for x-mpeg-4-flexmux, etc)
 
- for flexmux, again it may be better to use a=fmtp to specify the flexmux
  specific parameters (to avoid defining a new attribute type)

Cheers,
Colin