We were poking around a bit for information on far-end camera control, and ended up searching for references to H.281 in most of the documents being decided in January. As a result, we uncovered some inconsistencies that may require editorial correction of the decided texts of H.245, H.246, and H.323.

(1) H.245 section 2 refers to 1996 versions of H.281 and H.224. We can find only versions published in 1994. However, I note that although H.224 and H.281 are listed as references, they are not actually referenced in the text of H.245 anywhere, either by name or by the reference number. Either these references should be deleted from section 2, or the dates changed to "(1994)".

(2) H.246 refers to H.281 and H.224 in section A.9, but they are not included in the references in section 2. The solution here could be to simply remove section A.9, since it is "for further study"; if this is not done, H.281 and H.224 should be added to section 2.

(3) H.323 version 2 refers to H.281 and H.224 in section 6.2.7, but neither of these are included in the references in section 2. H.281 and H.224 should be added to section 2. Note that H.323 version 1 had the same problem.

The reference in H.323 and the presence of DataApplicationCapability.application.h224 in H.245 seem to imply that H.281/H.224 can be used in H.323 terminals. It would seem fairly straight-forward to open a camera control data logical channel associated with a video channel and send H.281 commands. Does anybody actually do that today? Has it even been prototyped? Have details been worked out, such as whether it would be a TCP or UDP connection? Or was this intentionally postponed while T.130 work proceeded? If that's the case, should it be resurrected considering the state of T.130? Is H.281 simply considered not suitable for use on IP/Internet (due to latencies)? If so, is there desire to work out H.245 extensions to do the same things? I'm sure you've all discussed this before I was around; sorry.

-- Toby ___________________________________________________________ Toby Nixon, Program Manager - NetMeeting http://www.microsoft.com/netmeeting Microsoft Corporation, Applications and Internet Client Group, Redmond WA USA +1 (425) 936-2792 Fax: +1 (425) 936-7329 mailto:tnixon@microsoft.com