1. A method of decoding a video signal having a current block to be decoded with a decoding apparatus, comprising: determining a scanning type of the current block, the scanning type comprising at least one of a vertical scan, a horizontal scan or a zigzag scan; obtaining residual coefficients relating to the current block based on the determined scanning type; obtaining inverse-quantized residual coefficients by inverse-quantizing the residual coefficients; determining, based on a transform skip mode index specifying a transform skip mode of the current block, the transform skip mode of the current block, wherein the transform skip mode of the current block is determined to be one of one or more transform skip mode candidates, wherein the one or more transform skip mode candidates include at least one of a 2D transform mode, a horizontal transform mode, a vertical transform mode or a non-transform mode, and wherein a number of the one or more transform skip mode candidates is different according to a size or a shape of the current block; obtaining, based on the determined transform skip mode of the current block, residual samples from the inverse-quantized residual coefficients; obtaining prediction samples of the current block by performing a prediction on the current block; and reconstructing the current block by using the residual samples and the prediction samples, wherein when the transform skip mode of the current block is determined to be the non-transform mode, the residual samples are obtained by scaling the inverse-quantized residual coefficients in non-transformed rows and/or columns of the current block with a pre-determined value.