Method for random access to picture blocks in video pictures

A method for random access to picture blocks in a video picture composed of lines composed of pixels, which comprises the steps of:

• storing a first excerpt of a sub-picture in a first area of an access memory, the first excerpt being dimensioned such that it encompasses a main picture block having x pixels in a horizontal direction of the sub-picture and also at least one adjacent picture block adjoining it in the horizontal direction and having equivalent dimensions;
• reading out one of the main picture block and the at least one adjacent picture block from the access memory;
• storing a portion of the sub-picture which adjoins the first excerpt horizontally in a second area of the access memory while a picture block is being read out, the portion being chosen such that it contains x pixels in the horizontal direction and, in a vertical direction, as many of the pixels as the first excerpt has in the vertical direction;
• and
• storing a second excerpt of the sub-picture having equivalent dimensions as the first excerpt in the first area of the access memory, the second excerpt being shifted horizontally relative to the first excerpt such that it completely contains the portion of the sub-picture stored in the second area.