METHOD OF CLIPPLING TRANSFORMED COEFFICIENTS BEFORE DE-QUANTIZATION

摘要

A method of clipping transformed coefficient before de-quantization in video and image compression and an associated apparatus are provided. The method comprises: setting clipping condition based on a transform size, a source bit-depth, and/or a quantization parameter; and adaptively clipping transformed coefficient according to the clipping condition. In some embodiments, the adaptive clipping may be further simplified to one-parameter-dependent clipping, or even to unconditional fixed-range clipping. With the provided method and associated apparatus, undesired overflow in 32-bit de-quantization process is completely avoided.