C-cube Microsystems, Inc.

C-cube Semiconductor Ii Inc.

Kourosh Soroushian

Feng-Ming Wang

Fermi Wang

Siok Huang Tay

The present invention is directed to a method for encoding an uncompressed digital video bit stream. The video bit stream comprises successive frames, each of which includes one or more odd fields and one or more even fields. Such frames with more than two fields may result from a telecine process as discussed above. The inventive method comprises the steps of capturing successive frames of said video bit stream in an encoder system, determining statistics for each frame to make an encoding decision for the frame, the statistics for each frame being determined in a single field time, using a statistically valid subset of pixels from the frame, and encoding the frame in said encoding system in a manner responsive to said encoding decision to generate an encoded bit stream. In a preferred embodiment of the invention, the statistically valid subset of pixels has a checkerboard pattern. Illustratively, the encoding decision involves dropping a repeated field in a frame and inserting a repeat field flag into the encoded bit stream.

Repeat field detection using checkerboard pattern

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.

Growing community of inventors

Sunnyvale, CA, United States of America

Kourosh Soroushian