1. A video encoding method for use in a video encoder, the video encoding method encoding pixels of an image block in a digital image, the video encoding method comprising: predicting, using a processor, the pixels of the image block based on reference pixels spatially adjacent to the image block; encoding a difference between the predicted pixels of the image block and an original image block; and embedding the encoded difference within a bitstream, wherein said predicting the pixels of the image block includes performing, for each of the pixels of the image block: determining, for the pixel of the image block, at least one reference pixel adjacent to the image block; determining a spatial distance between the pixel of the image block and the at least one reference pixel, the spatial distance being determined by adding (i) a squared absolute value of a vertical distance between the pixel of the image block and the at least one reference pixel and (ii) a squared absolute value of a horizontal distance between the pixel of the image block and the at least one reference pixel; and predicting the pixel of the image block, wherein in said predicting the pixel of the image block: when the determined spatial distance is greater than or equal to a first distance, the pixel is predicted by smoothing the at least one reference pixel with a low-pass filter and using the smoothed at least one reference pixel; and when the determined spatial distance is smaller than a second distance that is smaller than the first distance, the pixel is predicted using the at least one reference pixel without smoothing the at least one reference pixel with the low-pass filter; and when the determined spatial distance is smaller than the first distance and greater than or equal to the second distance, the pixel is predicted as a weighted sum of (i) information obtained by predicting the pixel using the at least one reference pixel without smoothing the at least one reference pixel with the low-pass filter and (ii) information obtained by predicting the pixel by smoothing the at least one reference pixel with a low-pass filter and using the smoothed at least one reference pixel.