Subject: RE: [AVT] The use of RFC 2190 vs. RFC 2429 for transporting H.263video?

From: "Even, Roni" <[email-masked]>
Date: Mon, 29 Nov 2004 16:06:51 +0200

Hi,
This is the text from H.225 version 5

Annex E
E.1	H.263
An RTP payload format for H.263 video is specified in IETF RFC 2190 for
H.263 video bitstreams that do not contain the new features adopted in
version 2 (the 1998 version) of ITU-T H.263 (the features using
PLUSPTYPE or annexes subsequent to Annex H/H.263). An additional payload
format which supports the enhanced features of H.263 version 2
bitstreams will be specified at a later date. A legacy packetization
format widely used in industry (not as specified in IETF RFC 2190) may
only be used if the peer indicated support for this format in the
capability exchange.

ANNEX I
H.263+ video packetization
IETF RFC 2429 specifies the RTP payload format for H.263 video
bitstreams that contain the new "H.263+" features adopted in version 2
(dated 1998) of ITU-T H.263 (includes the features using PLUSTYPE or
Annex I/H.263 through Annex T/H.263).
The ability to support the H.263 payload format of RFC 2190 as specified
in Annex E is required for H.263 bitstreams which do not use the new
version 2 features of ITU-T H.263, because this support is needed for
compatibility with prior implementations. However, the new payload
format specified in RFC 2429 should be used even for bitstreams which do
not contain the new version 2 features, provided the newer payload
format is within the capabilities of the receiving terminals.

As can be seen from both annexes RFC2190 is not mandated here and on the
other hand annex I has the same recommendation as RFC2429. Annexes in
ITU document are normative!!!.

As for what is happening in the SIP world. There are not many shipping
products. Microsoft window messenger supports video/H263 using RFC2190
and will not support H263-1998 using RFC2429. That is why we had to send
in our SDP both media type parameters.
The IETF would like to move RFC2190 to historic state. This will mean
that legacy systems may use it but the expectation is that the new
products will use RFC2429-bis (H263-1998) and thus may be able to use
the optional parameters specified in the bis drafts enabling specifying
of annexes as well as frame rate per specific resolution.

An example is shown, this works even though the H263 line is not correct
but is there due to some implementations that we encountered and it does
not break for endpoint who do not understand the second line for BW my
suggestion is to use the new TIAS to specify the exact BW

a=rtpmap:96 H263-1998/90000
a=fmtp:96 CIF=1;QCIF=1;CIF4=2;SQCIF=1

a=rtpmap:34 H263/90000
a=fmtp:34 CIF=1;QCIF=1;CIF4=2;SQCIF=1

b=TIAS=320000

Roni Even

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Terje Vernly
Sent: Monday, November 29, 2004 1:16 PM
To: Ross Finlayson
Cc: [email-masked]
Subject: Re: [AVT] The use of RFC 2190 vs. RFC 2429 for transporting
H.263video?

Ross Finlayson <[email-masked]> writes:

> The first paragraph of RFC 2429 notes that it is preferred over the
> older RFC 2190 payload format - even for transporting the 1996 version
> of H.263.
> 
> However, today I read a claim that several legacy H.323
> videoconferencing systems (the names Polycom and Tandberg were
> mentioned) still use the older RFC 2190 payload format when sending
> H.263, and that some (perhaps different) videoconferencing systems
> will receive only the RFC 2190 payload format, and do not understand
> the RFC 2429 payload format ("video/H263-1998") at all.
 
> Can anyone confirm (or deny) this claim?  Basically, I'd like to know
> whether RFC 2190 is something that I (as an implementor of RTP-based
> software) should still be concerned with, or whether I can get away
> with supporting only RFC 2429?

Support for RFC2190 is mandatory for systems conforming to ITU-T
H.323.  Support for other packetization methods has to be signalled
explicitly within the capability exchange procedure and within logical
channel messaging.

In real life, H.323-systems that don't utilize the features of
H.263+(+) will most likely not support reception of RFC2429 packetized
H.263.

-- 
Terje Vernly
TANDBERG

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt