Digital video data quantization error detection as applied to

Abstract

Under one embodiment, a first and a second similarly constituted detector, and an OR gate coupled to the two detectors, are provided to a digital video system. The first detector detects quantization errors of numerically adjacent values in vertically adjacent pixels of a current frame. The second detector detects quantization errors of numerically adjacent values in horizontally adjacent pixels in the current frame. The OR gate is used to determine whether quantization errors of numerically adjacent values are detected in at least one of the two spatial dimensions of pixel adjacency in the current frame. In one variation of this embodiment, a potential quantization error lookup table that supports concurrent lookups for vertically and numerically adjacent quantization error detection as well as horizontally and numerically adjacent quantization error detection is used and shared between the two detectors. In an expanded embodiment, a third similarly constituted detector is further provided, and coupled to the OR gate. The third detector detects quantization errors of numerically adjacent values in temporally adjacent pixels of successive frames. The OR gate is used to determine whether quantization errors of numerically adjacent values are detected in at least one of the three dimensions of pixel adjacency. In a further expanded embodiment, a compensation corrector is further provided, and coupled to the OR gate. The compensation corrector prevents successive shifting/modifying of digital video data of horizontally/vertically/temporally adjacent pixels to the same value otherwise resulting from dynamic companding.