Patent ID: 9584830
Date: 2017-02-28
CPC Classifications: H04N

Claim:
1. An image decoding apparatus, comprising: an entropy decoder configured to restore an intra prediction mode and one-dimensional (1D) quantized coefficients; an inverse scanner configured to inversely scan the 1D quantized coefficients to generate quantized transform coefficients; an inverse quantizer configured to inversely quantize the quantized transform block using a quantization step size to generate a transform block; an inverse transformer configured to inversely transform the transform block to generate a residual block; an intra predictor configured to generate a prediction block corresponding to a current prediction block according to the intra prediction mode; and an adder configured to restore an original block by adding the residual block and the prediction block, wherein the inverse scanner restores a plurality of sub-blocks, which are generated by an encoder that divides the quantized transform block into the plurality of sub-blocks after quantizing the transform block when a size of the transform block is 8×8, by applying a first scan pattern determined according to the intra prediction mode to the 1D quantized coefficients, and restores the quantized transform block by applying a second scan pattern determined according to the intra prediction mode to the plurality of sub-blocks, wherein the first scan pattern is a scan order applied to the 1D quantized coefficients, and the second scan pattern is a scan order applied to each sub-block of the plurality of sub-blocks, wherein the first scan pattern is the same as the second scan pattern, and wherein the intra predictor includes: a reference pixel generator configured to generate reference pixels using available reference pixels of the current prediction block when reference pixels do not exist; a reference pixel filter configured to adaptively filter reference pixels adjacent to the current prediction block based on the selected intra prediction mode and size information of the current prediction block; and a prediction block generator configured to generate the prediction block of the current prediction block according to the intra prediction mode.