Video synchronization

Abstract

An encoder system includes an internal counter (PTS or presentation time stamp counter). The counter provides information which enables the encoder system to resynchronize itself in the event synchronization with the video input stream is lost. Preferably, the counter is implemented in software. The encoder system also include a comparator (preferably implemented in software). The comparator is able to determine if particular regions of the input video stream have been captured at an expected time according to the internal counter within a predetermined error window by comparing the actual capture time with the expected capture time. In general, if the encoder system is synchronized with the incoming video stream, each successive blanking or active region will be captured at its expected time according to the internal counter within a predetermined error window. In this event, the timing of the various modules of the encoder system (e.g., preprocessing, spatial encoding, etc.) is based on the actual timing of the capture of a particular region according to the internal counter. In the event synchronization is lost between the video input stream and the encoder system, the encoder system resynchronizes itself with the video stream. Further, encoding of previous successively captured regions is based on the expected capture time (rather than the actual capture time) until a predetermined number (e.g., four) of regions are captured at the expected time within the error window.