Method and apparatus for intra prediction within display screen
The present invention relates to a method and apparatus for intra prediction. The intra prediction method for a decoder, according to the present invention, comprises the steps of entropy-decoding a received bitstream, generating reference pixels to be used in the intra prediction of a prediction unit; generating a prediction block from the reference pixels on the basis of a prediction mode for the prediction unit and reconstructing an image from the prediction block and a residual block, which is obtained as a result of entropy encoding, wherein the reference pixels and/or the prediction block pixels are predicted on the basis of a base pixel, and the predicted pixel value can be the sum of the pixel value of the base pixel and the difference between the pixel values of the base pixel and the generated pixel.
1. The method of decoding a video signal with a decoding apparatus, comprising:
obtaining a residual coefficient of a current block from the video signal;
deriving an inverse-quantized residual coefficient by inverse-quantizing the residual coefficient of the current block;
deriving a residual sample by inverse-transforming the inverse-quantized residual coefficient of the current block; and
deriving a reconstruction sample of the current block by adding the residual sample and a prediction sample, the prediction sample being obtained based on reference samples adjacent to the current block, the reference samples comprising at least one of left neighboring samples or top neighboring samples,
wherein when the reference samples include an unavailable sample which is not used for an intra prediction, the unavailable sample is substituted for an available sample which is used for the intra prediction, the available sample being adjacent to the unavailable sample, and
wherein when the unavailable sample corresponds to at least one of the left neighboring samples other than a top-left neighboring sample, the available sample is located at a bottom side of the unavailable sample, and when the unavailable sample corresponds to at least one of the top neighboring samples, the available sample is located at a left side of the unavailable sample.
2. The method of claim 1 , wherein the prediction sample is obtained using filtered reference samples, the filtered reference samples being derived by applying one of multiple intra filters to the reference samples adjacent to the current block.
3. The method of claim 2 , wherein filter coefficients of the applied intra filter are [1, 2, 1].