Has Sigma solved the lip sync problem?

By Ken Kerschbaumer

Lip sync issues plague the entire broadcast and cable TV industry as digital encoding and decoding processes and transmission invariably lead to the audio and video portion of a signal becoming disconnected and out of sync.

Sigma Electronics believes it has found the answer with Arbalest, an encoding and decoding system that costs $19,900 and basically hooks the audio and video together via a two-bit piece of code. Turner has purchased 13 of the systems for use in sports production.

“When we began to analyze the audio lip sync issue two years ago we found the entire chain was broken but we decided to tackle the contribution portion of the chain,” says Bill Swilley, Sigma Electronics president and CEO.

In a typical sports application an Arbalest encoder would be placed in the transmission chain next to the IRD. Outgoing video signals than pass through the encoder that analyzes certain characteristics of the video signal like chrominance, luminance, motion, etc. and then creates a two-bit profile that is inserted into the Dolby AC3 stream and identifies that given frame of video.

When the signal then arrives in the network operations center it runs through a decoder that analyzes the exact same characteristics and, thanks to some complex algorithms, will generate a two-bit profile that matches the one on the encoding side.

“The two profiles will match allowing the system on the decode side to also match up the audio because the code is in the AC3 stream,” says Swilley.

Swilley says the system is an ideal fit for remote sports production backhauls as well as sending content from networks to affiliate stations.

For now the system doesn’t guarantee perfectly synched audio to the viewers at home because cable set-top boxes and TV sets do not currently have the ability to decode the two-bit code. But the key word is yet. Swilley says the ultimate vision is to have the decoding software in every set-top box and TV set tuner.

“It’s a Linux-based product so that’s something we can do,” he says.