METHOD AND APPARATUS FOR DEQUANTIZATION OF TRANSFORMED COEFFICIENTS

摘要

A method and apparatus for de-quantizing a transform coefficient from a quantization level are disclosed. Embodiments according to the present invention avoid overflow of the de- quantized transform coefficient by clipping the quantization level adaptively before reconstructing the transform coefficient. In one embodiment, the method comprises receiving a decoded quantization level for the transform coefficient of a transform unit, wherein the decoded quantization level is decoded by an entropy decoder or is being processed by the entropy decoder. The clipping range is determined and then the decoded quantization level is clipped to the clipping range to generate a clipping-processed quantization level. A de- quantized transform coefficient can be generated using the clipping-processed quantization level. In another embodiment, the decoded quantization level is always clipped to [-N, M], where M and N are positive integers.