Patent ID: 6215822
Filing Date: 2001-04-10
Classification: H04N

Abstract:
An integrated circuit that includes a video decoder having a motion compensation circuit for constructing a current picture based upon a motion vector in an input video stream by copying data to a portion of the current picture from a portion of a reference picture by relocating the copied data in the current picture by the value of the motion vector, comprising:a memory controller for controlling a multi-page memory arranged in logical rows and columns of memory locations, at least a portion of the memory locations collectively holding reference pictures, wherein the reference pictures include a plurality of reference blocks of data stored in a plurality of logical rows of pages of the memory such that the stored data that are horizontally contiguous across any rectangular area of the reference picture lies in the same logical row of logically adjacent pages;decoding circuitry operable to extract the motion vector from the input video stream;a motion compensation circuit operable, in response to the extracted motion vector, to identify a contiguous rectangular portion of a reference picture containing at least one sub-portion each occupying a contiguous rectangular area thereof and to generate a signal for reading said portion of the reference picture from the memory by communicating a separate memory request to the memory controller for each such logical row of pages on which each sub-portion of said portion of the reference picture is stored, and by communicating a plurality of such separate memory requests to the memory controller when said portion of the reference picture includes a plurality of such sub-portions, each request including data from only a single logical row of logically adjacent pages of the memory;the memory controller being operable to retrieve the horizontally contiguous data of said any rectangular area from a plurality of logically adjacent pages in one logical row thereof in response to one of said separate memory requests from the motion compensation circuit; andwhereby the integrated circuit is operable to read each sub-portion of said portion of the reference picture from the memory, one in response to each memory request.