Video decoder with five page memory for decoding of intraframes,

Abstract

Compression algorithms for digital video signals are based on processing of data blocks of frames which are of three types, i.e. intraframes, predicted frames, and interpolated or bidirectional frames (B). The memory space of the decoder is arranged in the form of five pages, four pages of which are used for each storing a field of the intraframe or predicted type. The fifth page is divided into sections each of which can store a line of blocks of a field of a bidirectional frame B. The bidirectional frames are decoded in successive stages of one line of blocks at a time, and the lines of blocks which are being decoded are stored progressively each time at the address in memory of a line of blocks the contents of which have already been displayed. The necessary memory space of the decoder is thereby reduced from six pages to five pages.