Communications integration moves closer

Electronic News, Jan 23, 1995 by Reinhardt Krause

SANTA CLARA, CALIF.--The Intelled Personal Conferencing Work Group (PCWG) last week took the wraps off version 1.0 of its open specification for interoperable desktop conferencing products--including a new variant of Indeo Video and an audio codec initially based on Europe's GSM algorithms. However, application programming interfaces (APIs) will not arrive for software developers until later this year when a second version is released.

In a development related to the APIs, the PCWG is expected to hold meetings with the "Versit" group for computer/telephony integration formed last year by AT&T, Apple Computer, IBM and Siemens. Versit is developing common specifications for H.320 ISDN-based videoconferencing and is forming its own APIs for exchanging data, voice and video.

Products based on the new PCWG specification from core members are expected to arrive in Q3 this year. Intel is also readying a new 5 Mbps serial bus to support the new specification's plementation for `end-point' platforms such as PCs.

Michael Glancy, chairman of the PCWG and Intel's director of desktop conferencing architecture and core technologies, said the PCWG is moving aggressively to issue the second round of specifications--which would enable more third-party implementations. The second specification will include improved LAN capability with gateways; extensions for conferencing over standard phone lines (POTs); enhanced network services, such as video mail; and support for Digital Simultaneous Voice and Data (DSVD).

The initial specification includes a new variant of Intel's Indeo video compression/decompression algorithms that is tailored for ISDN's low data rates and provides scalability in resolution, frame rate and bandwidth. The new Indeo Video C3.0 also uses a more efficient variable length decoder and additional post-processing aids in motion estimation.

Integrated Information Technology (IIT) has disclosed (EN, July 18, 1994) that it is porting the Indeo video variant to its RISC-based programmable architecture for H.320-to-Indeo transcoding--reportedly at the behest of PCWG members such as Compression Labs Inc. and VTEL.

Intel and AT&T Business Communications Services also ironed out a videoconferencing interoperability pact last year (EN, Aug. 29, 1994) in order to make AT&T's H.320 standard-based WorldWorx services interoperable with Intel's PC-based Proshare personal conferencing products.

Although AT&T will offer transcoding over its networks--largely in multipoint control units (MCUs), AT&T Microelectronics had expressed a continued reluctance to port the new Indeo variant to its devices in order to support end-equipment. However, Mr. Glancy last week said he still expects AT&T's video codecs to support Indeo video C.

Unlike H.320, the PCWG uses a packetized structure for multiplexing audio, video and data. The packetized scheme allows documents, applications, graphics, audio and video to move across any network types.

The new Indeo video algorithms are defined in the PCWG's new specification and can be implemented by its members; Intel is also licensing the software used in its i750 processor-based board products. Mr. Glancy added: "You can do C algorithms as specified on a Pentium class machine and obviously that's what we're driving toward."

He added that new Indeo variant "is substantially lower in complexity than the H.261 codec in H.320 right now by at least a factor of 2x in the Mips ratio. As we go forward and there is more Mips available in the host other compression algorithms, like H.261, will sit more comfortably.

"As we go forward we are going to be very flexible on the audio and video codecs that will be used," Mr. Glancy said. "We view the applications as being broader than pure conferencing and may include person-to-a-server and so forth. Some of these may require different quality levels of compression for audio and video, different bit rates and other attributes.

The choice of the audio compression algorithms used in Europe's Global System for Mobile Communications (GSM) systems came as a surprise. The PCWG last week said that France Telecom and Deutsche Telekom have now joined as core members; the group already included Ericsson and Olivetti.

Mr. Glancy said he expected another audio codec--with better performance--to be part of the second PCWG to be released later this year. The GSM audio compression algorithms provided the moderate to low complexity that some PCWG members had sought. However, Mr. Glancy said that another audio codec would provide more scalability in performance over various communications environments, such as LANs, POTs and ISDN.

He noted that even under the first specification equipment makers have the option of designing in proprietary audio algorithms. The new specification features a communications structure--a negotiating scheme at front-end connection--that enables end equipment to signal their audio/video capabilities, security measures, as well as H.320 compliance.

Mr. Glancy said intel has been in touch with one member of the Versit initiative and plans to hold meetings, including the PCWG, with the group. "We're going to be setting up meetings and we'll see what areas of overlap there are. We'll see how we could collaborate.