An invention for measuring, maintaining and correcting synchronization between signals which suffer varying relative delays during transmission and/or storage is shown. The preferred embodiment of the invention finds particular use in measuring the relative delay between multiple audio signals and an associated video signal of a television type program which is compressed via MPEG or other compression for a transmission and/or storage system. The invention marks the video signal at a time when a particular event in the associated audio occurs. The mark is carried with the video throughout the video processing. After processing the same event in the audio is again identified, the mark in the video identified, the two being compared to determine the timing difference therebetween.