H.323 Annex I

Adam Li adamli at icsl.ucla.edu
Tue Feb 13 01:40:10 EST 2001

Dear Mr. Baese, experts,

> concerning your document APC 2018 "Protection Procedure":
> c) If the protection is actually done with level p-1 why do one has
>     to keep level p somehow ? In opposition to the written text is
>     packet #3 in your figure.
> d) Can you please explain the meaning of "packet" in
>     every case it is mentioned within this paragraph ?

The grouping rule in the protection procedure is now reworded. It now reads:

a. A media packet can only be protected at each protection level once.

b. For a media packet to be protected at level p, it must also be
   protect at level p-1.

c. If an FEC packet contains protection at level p, it must also
   contain protection at level p-1.

I hope it is clearer now. Let me know if there is any further questions.

> We are supposed to perform the test reproducible for everybody else
> within the standardization community. Which public available software
> for H.263 we are going to use ?

This question may be better answered by Q.6/16 (Video Coding Experts Group),
who works on standardizing the H.263 video codec. All the algorithms for
H.263 are detailed in the H.263 and TMN documents in Q.6. As far as I know,
UBC (University of British Columbia) has a (semi-official) sample software
implementation of the codec.

Hope it helps.

Adam Li

Adam H. Li
Image Communication Lab                    (310) 825-5178 (Lab)
University of California, Los Angeles      (310) 825-7928 (Fax)

More information about the sg16-avd mailing list