Ibiquity’s Mystery Codec: What is It?

Ibiquity has quietly begun inviting broadcast engineers to its Columbia, Md. headquarters to hear its new or upgraded codec. Two engineers who have heard the codec so far praised Ibiquity’s efforts.
The engineers heard the demo of various music and talk material on CDs sent through an Ibiquity reference exciter and receiver, plus one consumer receiver. One said, “It was not a simulation using a PC.”
In separate demonstrations on different days, the engineers said they heard FM at 96 kbps and 64 kbps, the latter being the bit rate the primary channel would need to be for stations that wish to split their programming and have a secondary audio channel, a concept that NPR, Harris and Kenwood plan to test soon.
The engineers also heard AM at 36 kbps. Ibiquity has been focusing on improving the codec performance, especially on AM at low bit rates, since May. That’s when the standards-setting body, the NRSC, said it did not believe Ibiquity’s PAC codec delivered broadcast-quality audio on AM at low bit rates. As a result, the group suspended all standards-setting efforts, for both AM and FM.
Geoff Mendenhall, vice president of advanced product development for Harris Broadcast, said the progress was “phenomenal to the point where we are satisfied and we think broadcasters will be too.”
NPR Senior Engineer Jan Andrews described the improvements as “startling.”
Previously, NPR was one of the more vocal critics of Ibiquity’s AM audio performance. Andrews said of the demo, that he found the audio quality “very acceptable.”
In a memo to stations on a technical public radio list serve, Andrews stated: “Assuming Ibiquity is able to deliver the demonstrated level of performance in the real world (which seems possible given that we were listening through reference exciters and receivers and one consumer receiver), I believe there will be compelling audio quality incentives for stations to adopt HD Radio.”
More engineers are expected to make the trek to Maryland for a demo this week and next.
Reportedly, there will be a further demo at NPR later this month.
Ibiquity declined comment on the demos, and particularly on what codec is being used. The spokesman said the company continues to work on the issue and hopes to go public with details soon.