METHOD AND APPARATUS FOR PERFORMING CLIPPING DURING DE-QUANTIZATION AND INVERSE TRANSFORMATION IN VIDEO DECODING

摘要

PURPOSE: An inverse conversion method for clipping data of inverse quantization and inverse conversion in a video decoding process and a device thereof are provided to clip input data of first inverse conversion and second inverse conversion for storing intermediate data and output data, thereby preventing overflow of registers. CONSTITUTION: An inverse conversion device generates conversion coefficients by inverse quantization of quantized conversion coefficients of a received current block and clips the generated conversion coefficients within ranges of a first maximal value and a first minimal value which are determined based on a size of the current block(41,43). The inverse conversion device performs first inverse conversion for a clipped conversion coefficient. The inverse conversion device clips generated intermediate data within ranges of a second maximal value and a second minimal value which are determined based on the size of the current block and internal bit depth(45). The inverse conversion device performs second inverse conversion for the intermediate data(47). [Reference numerals] (41) Receive quantized conversion coefficients; (43) Generate conversion coefficients by dequantization and clip the generated conversion coefficients into a determined first maximum value based on a block size; (45) Perform first dequantization for the clipped conversion coefficients and clip intermediate data generated by the first dequantization into a determined second maximum value based on the block size and an internal bit depth; (47) Perform second dequantization for the clipped intermediate data; (AA) Start; (BB) End