Viewers watching programs on large home-theater displays are more likely to notice annoying lip-sync errors. Caused when synchronization is lost between audio and video signals, the problem has become more acute in sophisticated production environments with heavy signal processing.
Lip-sync errors can occur whenever there are delays introduced in the equipment chain. The timing of common devices such as frame synchronizers, DVEs and even CCD cameras can contribute to lip-sync problems.
To help track down these timing errors, Pro-Bel, a manufacturer of broadcast infrastructure equipment, has created VALID8, an updated HD-capable, eight-channel audio measurement device designed to deal with audio/video synchronization issues. VALID8 is part of Pro-Bel's Vistek line of modular interface components.
VALID8 provides users with a method of assessing timing issues in a mobile or studio production chain so that they can be found and eliminated. VALID stands for Video and Audio Line-up and IDentification. The "8" designation expands it for HD use.

A internal generator produces four separate signals: a user-definable test pattern background; two dynamic display elements (the video equivalent of a film clapper board); up to eight channels of audio; and ID-up to four lines of user-defined captions plus a central indication of the original standard and audio level.
Users can detect A/V delay on a purely visual/aural basis. The VALID8 reader can display timing errors to the nearest millisecond. It can also indicate whether there has been any channel crossover or if there is phase error between left and right. The actual level of signals can be displayed in a variety of metering formats.
VALID8 can handle just about any signal, including those that are compressed, recorded, replayed and transmitted. Provided some video and audio survives, then the VALID signal can be measured for video/audio delay, Pro-Bel says.
For more information, visit http://www.pro-bel.com.