Method of image compression and device for implementing this method
OwnerPhilippe Guillotelinventor
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Abstract
The invention relates to a method of image compression, especially of the MPEG2 type, in which the images are coded according to groups (GOPs) each of which comprises N images, with an I image coded in intra mode, P images predicted as a function of the intra image I or of the preceding P image, each P image being preceded and followed by n bidirectionally predicted B images, n possibly being zero. The number M=n+1 represents the structure of the group. At least one parameter characterizing the source images which are to be coded according to a group is determined using a test coding (70), and the numbers N and M are made to depend on this parameter or these parameters. In the course of the test coding, defined values are conferred on N, M, and on the quantisation interval Q.
Claims20
Method of image compression in which the images are coded according to groups (GOPs) each of which comprises a number N of images, N representing the length of the group, which includes an I image coded in intra mode, P images predicted on the basis of the intra image I or of a preceding P image, each P image being preceded and followed by n bidirectionally predicted images B, n possibly being zero, the number M, which is equal to the number n increased by one unit, representing the structure of the group, wherein at least one parameter is determined characterizing the source images which are to be coded according to a group and wherein the length N and the structure M of the group are made to depend on this parameter or these parameters.
Dependencies are inferred from the claim text.