RE: [AVT] Interop issue with H263-1998

["Even, Roni" <roni.even at polycom.co.il>]

Guido,
I think that the conclusion is that there is no interoperability if you use H263-1998 payload without the optional parameters. Still I would expect such terminals to send baseline H.263 since otherwise they cannot know if the receiver support any of the optional H.263 annexes
Roni 


> -----Original Message-----
> From: Franceschini Guido [mailto:guido.franceschini at telecomitalia.it]
> Sent: Monday, September 10, 2007 1:41 PM
> To: Even, Roni; avt at ietf.org
> Cc: Paltro Pier Carlo
> Subject: RE: [AVT] Interop issue with H263-1998
> 
> Thanks for the background.
> 
> Actually I was analyzing an interop issue where one terminal generates
> H263+ using H263-1998 with no FMTP line, while the other assumes no H263+
> annexes are being used and so raises an error on reception of H263+
> syntax.
> I was trying to understand which of the two terminals is compliant to the
> RFCs rules, and ... hitted into the problem :(
> 
> My conclusion is that it is legitimate to generate H263+ syntax when H263-
> 1998 has been negotiated and no FMTP line has been provided, and that
> paragraph 8.1.1 of RFC 4629 is inaccurate.
> 
> Best regards
> Guido
> 
> 
> > -----Original Message-----
> > From: Even, Roni [mailto:roni.even at polycom.co.il]
> > Sent: lunedì 10 settembre 2007 11.09
> > To: Franceschini Guido; avt at ietf.org
> > Cc: Paltro Pier Carlo
> > Subject: RE: [AVT] Interop issue with H263-1998
> >
> >
> > Guido,
> > I have to agree that systems that tried to use the payload
> > type H263-1998 before RFC 4629 may send any annexes available
> > in H.263+, not all of them since that may be not feasible. So
> > it was really un-specified before RFC 4629.
> >
> > The big motivation for RFC 4629 was because the video
> > conferencing manufacturers, who were the major users of
> > H.263+ were trying to support SIP (Moving from H.263) and ran
> > into SDP problems.
> >
> > When writing the draft, the assumption was that there were no
> > real implementations using H.263-1998 but mostly H263 or
> > H263-200 with profile and level optional options.
> >
> > Roni
> >
> > !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> > A consensus means that everyone agrees to say collectively
> > what no one believes individually
> > !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> >
> > > -----Original Message-----
> > > From: Franceschini Guido
> > [mailto:guido.franceschini at telecomitalia.it]
> > > Sent: Tuesday, August 21, 2007 6:49 PM
> > > To: avt at ietf.org
> > > Cc: Paltro Pier Carlo
> > > Subject: [AVT] Interop issue with H263-1998
> > >
> > > Dear all,
> > >
> > > I have an issue with the definition of the H263-1998 media type.
> > > In the RFC 2429, no optional parameters are defined,
> > implying that any
> > > valid H263+ stream could be streamed.
> > > In the RFC 4629, that obsoletes 2429, various optional
> > parameters are
> > > specified, which allow specifying the (decoder) support to
> > the various
> > > annexes.
> > >
> > > What confuses me is the following statement in RFC 4629,
> > concerning H263-
> > > 1998
> > >
> > >    Interoperability considerations:
> > >
> > >       These are receiver options; current implementations
> > will not send
> > >       any optional parameters in their SDP.  They will ignore the
> > >       optional parameters and will *** encode the H.263
> > stream without any
> > > ***
> > >       of the annexes.  Most decoders support at least QCIF
> > and CIF fixed
> > >       resolutions, and they are expected to be available
> > almost in every
> > >       H.263-based video application.
> > >
> > > Indeed my understanding would be quite different, and I
> > would have written
> > > instead:
> > >
> > >       These are receiver options; current implementations
> > will not send
> > >       any optional parameters in their SDP.  They will ignore the
> > >       optional parameters and will *** encode the H.263+ stream with
> > > possibly all ***
> > >       of the annexes.  Most decoders support at least QCIF
> > and CIF fixed
> > >       resolutions, and they are expected to be available
> > almost in every
> > >       H.263-based video application.
> > >
> > >
> > > Any clarification would be welcomed
> > >
> > > Best regards
> > > Guido Franceschini
> > > --------------------------------------------------------------------
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