Vendors eye ITU conferencing specs

Electronic News, April 3, 1995

GENEVA, SWITZERLAND - While putting the finishing touches on the video coding portion of the new videoconferencing standard recently renamed H.324 (EN, March 13), an International Telecommunications Union (ITU) group here last week also began work on a new specification for videophone terminals working over mobile radio networks.

H.324, the plain old telephone service (POTS) based standard, will operate over regular analog-based telephone lines. H.324 is considered stable enough for silicon efforts and other product development to be under way - Integrated Information Technology and Siemens at CeBIT recently demonstrated a board, based on their chipset, implementing the low-bit-rate specification.

In addition to addressing interoperability issues within the POTS-based videoconferencing area and compatibility with ISDN-based systems, the new H.32P specification may jump-start products with price-points and performance appealing to more end-users. The overall H.32P standard also includes a basic interoperability mode so that public switch telephone network (PSTN) endpoints can interoperate with ISDN endpoints, so the video would not have to be transcoded. When combined with V.34 modem capability, the overall audio/visual system performance is said to be significantly improved over earlier videophone terminals.

The ITU group last week was still examining the possible incorporation of other video coding algorithms in addition to the sub-pixel motion estimation and three-dimensional coding already approved. As of last week, still under scrutiny as possible mandatory items or as options are syntax-based arithmetic coding, advanced prediction mode, and PB-frames.

Meanwhile, while the H.324 standard for public switched telephone networks is making good progress toward approval, the ITU group will begin working on a spec for videophone terminals working over mobile radio networks. There may be some overlap between the new mobile standard for lowbit-rate video telephony and the MPEG-4 compression standard, which began to surface last year in Japan during the Panasonic Industry 94 exhibition (EN, May 22, 1994).

While the mobile specification is some time off from being finalized, semiconductor vendors will be targeting the H.324 specification - with programmable architectures seen as having an advantage. AT&T Microelectronics contends its AVP chipset also has a programmable flavor - but IIT has already signed a deal with the consumer products division of AT&T, which will use the LVP in the next-generation 2500 videophones.

"We need to be in the (H.32P) market and fuel that market with low-cost devices to get the cost of endpoint equipment down as well as the quality up," said Peter Ahimovic, AT&T product manager for video solutions. "It needs to be attacked on two fronts: one is to get the costs down for the consumer market and the other is to get the quality up. The current videophones out there don't hit the market yet."

Price-points for H.32P based boards have not been established but Siemens and ITT are moving aggressively based on their earlier chipset partnership announced last year. That chipset uses IIT's video communications processor (VCP). A plug-in card based on the IIT/Siemens chipset which supports the ISDN-based H.320 standard has an estimated price of $670 and Pots-based videoconferencing should be even less costly to end-users.

SGS-Thomson, meanwhile, is also eyeing the new POTS-based standard. At the recent International Solid States Circuit Conference, SGS unveiled a consumer-oriented single-chip codec for consumer videophones that targets the existing H.261 standard. An SGS spokesperson said a new version is under way that could also support the H.26P video portion of the upcoming H.32P standard.

At Texas Instruments, the company is planning to demonstrate H.32P compatible silicon by year-end, said Julie Gallagher, TMS320C80 (MVP) marketing manager, during CeBIT. Long-range, TI plans to have a single-chip H.32P device in the sub-$100 range by 1997; however, it will be a stripped down, code-compatible version of the very high-end MVP.

TI's short-range goal is to make its C80 customer platforms interoperable with the H.32P spec. TI, meanwhile, at CeBIT introduced a new H.320 software library for its C80 digital signal processor.

Although parts of the video coding specification still need to be ironed out, the H.32P standards group was able to come together much quicker for speech coding. The audio algorithm being used was grafted by France Telecom and the DSP Group, which had proposed similar methods. The speech coder will run at 5.3 and 6.3kbps. Commenting on the ITU selection of the speech compression technology jointly proposed by DSP Group and France Telecom to be included in the planned ITU standard, DSP Group president and CEO Eli Porat indicated that with the multimedia market, videotelephone represented the most difficult task of allowing different products to communicate with each other using the speech files.