DTV lip-sync test using time-indexed audio and video signals without effect on program

A new lip-synchronization (lip-sync) test method using audio and video signals for DTV is presented. The proposed method does not interfere with or have any effect on the program being broadcast, as the time-indexed lip-sync test signals (TILTS) are embedded in a hidden region. The video TILTS is embedded into transient effect areas outside the active pixel region, making it invisible on-screen. Experimental results confirm that the time difference between audio and video signals can be easily measured at any time from the TILTS in the decoder outputs.