Patent ID: 6920178

Claim:
A method of switching video component(s) of a first digital audio-visual program onto video component(s) of a second digital audio-visual program, each video component including, in the order of presentation, an ordered sequence of pictures which are either Intra pictures (denoted by I) or predictive pictures (denoted by P) or bidirectional pictures (denoted by B), each Intra picture referring to no other picture, each predictive picture referring to the Intra picture or to the predictive picture preceding it, each bidirectional picture being able to refer to two non-bidirectional pictures Intra or P, either to the Intra picture or to the predictive picture preceding it or to the Intra picture or the P picture following it, or to a combination of the two preceding or following Intra or predictive pictures, the method comprising (a) switching at a switching time following the end of a picture of the first program after the switch command onto the picture of the video component of the second program which is present at said time, and (b) replacing, as seen in the order of transmission, each picture other than Intra of said second program component, where said latter picture is situated between the switching time and the beginning of the next Intra picture of said second program component, with a picture having the coding thereof being carried out independently of the picture data of the replaced picture and of the contents of the pictures to which the replacement picture refers, the replacement pictures being included in a sequence of pictures which includes, as seen in the direction of transmission, alternating predictive and bidirectional pictures, the first predictive replacement picture P referring to the last predictive picture P or Intra picture I of the first-program video component, then each following predictive replacement picture P referring to the predictive picture P which precedes it, and each bidirectional replacement picture B referring only to the predictive picture P which precedes it, the number of bidirectional pictures B between two predictive pictures P being equal to that encountered in the first-program video component, and the motion estimating vectors of each replacement picture being set to a zero value.