Heuris, a St. Louis-based manufacturer of video compression and processing tools, is helping Maine Public Television inform its viewers of ever-changing multichannel DTV choices through a low bitrate "barker" channel.
Public broadcasters have long touted DTV's ability to offer multiple standard definition educational feeds to viewers by day and a single HDTV channel by night. However, with the reality, came a problem. How, in such a constantly changing program line-up, do viewers know where they should tune in to see their favorite programs at any given time?
Ideally, the viewer's DTV receiver would recognize the different bandwidth allocations and handle the situation gracefully. In reality, Maine Public Broadcasting (MPT) found that not all DTV receivers are created equal.
The solution was the creation of an informational "barker channel." It’s a “trickle” stream using small amounts of simple graphics or audio data to inform DTV viewers if programming is suspended on a specific channel and where to tune elsewhere.
Easier said than done, the Maine broadcaster found. It turns out that very few DTV encoders can be set for bit rates of less than 1.5 Mbps for video program streams. This is where Heuris came in, with their MPEG Power Professional DTV SD encoder, a device that will digitize an MPEG stream at virtually any bit rate.
Dave Roy, director of telecommunications at MPT, said they simply encoded a compliant MPEG stream from a fixed graphic with the Heurus encoder at less than 300 Kbps per second, saved the resulting file to a server, and then played it through the station’s DTV multiplexer.
Best of all, “It worked great,” he said, noting that the problem was solved at a cost of less than $5,000 per encoder.
For more information visit www.heuris.com.
