Chris,
Each H.320 frame (ignoring optional encryption) is 640 bits (for clear channel) of which 16 bits are dedicated to FAS (Frame Alignment Signal) and BAS (Bit-rate Allocation Signal). 16 / 640 * 100 = 2.5 % overhead. See ITU-T H.221.
Since H.323 overhead is based on payload size (which varies with codec output and network characteristics), more parameters are needed to calculate the overhead. See ITU-T H.225. A good, general source is "Videoconferencing and Videotelephony," Richard Shaphorst, Artech House, Inc., (c) 1996.
Barry
At 09:25 AM 2/11/00 -0500, you wrote:
Hi all
Would someone know the % of overhead in H.323 & H.320
Thanks for any help you can provide
Chris Christopher Iles Senior Technologist COMMUNICATIONS RESEARCH CENTER e-mail: christopher.iles@crc.ca 3701 Carling Ave Tel office: 613 998 2734 Ottawa, Ont. K2H 8S2 Ops Room : 613 998 2374 ATTN: BLDG 46