Caching method and apparatus for video motion compensation
OwnerStephen Molloyinventor
Life of this patent
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Abstract
A method and apparatus for motion compensation using a cache memory coupled to the motion compensation circuitry. The motion compensation method takes advantage of the fact that significant spatial overlap typically exists between a plurality of blocks that make up a macroblock in a motion estimation algorithm. Accordingly, a region of pixels may be stored in the cache memory and the cache memory may be repeatedly accessed to perform interpolation techniques on spatially adjacent blocks of data without having to access main memory, the latter being extremely inefficient and wasteful of memory bandwidth.
Claims46
A method to decode image data using a motion compensation circuit coupled to a cache memory, the cache memory for storing pixel data to be input to the motion compensation circuit, the method comprising:
- storing the pixel data in the cache memory comprising one or more blocks of pixels having a variable offset from reference blocks;
- retrieving the pixel data from the cache memory;
- inputting the pixel data into the motion compensation circuit;
- and
- interpolating the pixel data to a fractional offset of the one or more blocks of pixels.
An apparatus to decode image data comprising:
- a control interface;
- a cache memory coupled to the control interface, the cache memory configured to hold image data comprising regions of pixels on a display;
- a memory bus interface coupled to the control interface;
- a motion compensation interpolation datapath coupled to the cache memory;
- and
- a motion compensation circuit coupled to the motion compensation interpolation datapath.
An apparatus to decode image data, comprising:
- a control interface;
- a coordinate-to-cache address translator circuit coupled to the control interface;
- a cache memory coupled to the coordinate-to-cache address translator circuit, the memory cache configured to store blocks of pixel data;
- a motion compensation interpolation datapath coupled to the cache memory;
- a motion compensation circuit coupled to the motion interpolation datapath and configured to interpolate the blocks of pixel data received from the cache memory;
- a cache-to-physical address translator circuit coupled to the cache memory;
- and
- a memory bus interface coupled to the cache-to-physical address translation circuit.
An apparatus integrated in a mobile device to decode image data comprising;
- control interface means for receiving pixel data coordinates;
- coordinate address translation means for translating coordinate data to cache addresses;
- physical address translation means for translating cache addresses into physical addresses;
- a cache memory for storing regions of pixel data;
- a memory bus interface for issuing read commands to a main memory;
- and
- motion compensation means coupled to the cache memory for receiving regions of pixel data and interpolating blocks of pixels within the regions.
Computer-readable media embodying a program of instructions executable by a computer program to perform a method to decode image data using a motion compensation circuit coupled to a cache memory, the cache memory for storing pixel data to be input to the motion compensation circuit, the method comprising:
- storing the pixel data in the cache memory comprising one or more blocks of pixels having a variable offset from reference blocks;
- retrieving the pixel data from the cache memory;
- inputting the pixel data into the motion compensation circuit;
- and interpolating the pixel data to a fractional offset of the one or more blocks of pixels.
Dependencies are inferred from the claim text.