Patent ID: 6429902
Filing Date: 2002-08-06
Classification: H04N

Abstract:
An apparatus for synchronizing an audio/video (A/V) bitstream between a transmitting encoder for transmitting said A/V bitstream and a receiving decoder for receiving said A/V bitstream, said decoder associated with said apparatus, wherein said encoder inserts a plurality of program clock reference (PCR) time stamps into said bitstream, said apparatus comprising:a PCR extractor for extracting the plurality of PCR time stamps from the A/V bitstream; a local clock for generating a plurality of local time count (LTC) time stamps; a differencer for determining a PCR increment interval from said plurality of PCR time stamps and a LTC increment interval from said plurality of LTC time stamps; an evaluator for comparing said PCR increment interval to said LTC increment interval so as to determine an increment difference, wherein if said increment difference is nonzero said evaluator calculates an audio sample number for duplication or elimination of an audio sample in an audio bitstream and a video number of video pixels or video frames for duplication or elimination of a video pixel in a video bitstream; an audio sample buffer for duplicating said audio sample in said audio bitstream if said increment difference is greater than zero, called underflow, and for eliminating said audio sample in said audio bitstream if said increment difference is less than zero called overflow; and a video mixer for duplicating said video pixel in said video bitstream if said increment difference is underflow, and for eliminating said video pixel in said video bitstream if said increment difference is overflow.