Patent ID: 6269120
Filing Date: 2001-07-31
Classification: H04N

Abstract:
A method for splicing of new picture data into a digital video stream, that video stream having been compressed according to an MPEG compression standard, the method comprising the steps of:attaining a start buffer fullness and end buffer fullness parameters of data in said digital video stream that is being replaced by new pictures, said start and end buffer fullness parameters being represented as a difference between an Initial Buffer Fullness and the accumulation (E) of the difference between the pictures' actual bit usage and the average of bits per picture (Ba), assuming a constant picture target, where ##EQU5##determining the number of new pictures to be spliced in;calculating the change in an average bits per picture data unit, said calculation based on said start buffer and end buffer fullness parameters and a number of new pictures to be spliced, said change being calculated as Ba(new) ##EQU6##calculating the precise bit allocation for each new picture based on said calculated average bits per data unit and a type of said new picture;encoding the new picture data into the data stream so that the number of bits used does not exceed a target; andpadding the new data if bits used to encode the new data into the data stream are fewer than the target.