Abstract: An image coding device is provided with a determination unit which determines whether to apply an orthogonal transform to a transform block obtained by dividing a prediction difference signal indicating a difference between an input image and a predicted image or perform a transform skip by which the orthogonal transform is not applied, and an orthogonal transform unit which performs processing selected on the basis of the determination, the image coding device comprising a quantization unit which, when the transform skip is selected on the basis of the determination, quantizes the transform block using a first quantization matrix in which the quantization roughnesses of all elements previously shared with a decoding side are equal, and when the orthogonal transform is applied to the transform block on the basis of the determination, quantizes the transform block using the first quantization matrix or a second quantization matrix that is transmitted to the decoding side.

Abstract: A partial decoding circuit with inverse second transform has a transpose buffer, a first-direction inverse residual transform circuit, and a second-direction inverse residual transform circuit. The transpose buffer stores an intermediate inverse residual transform result. The first-direction inverse residual transform circuit processes an inverse quantization output to generate the intermediate inverse residual transform result to the transpose buffer. The second-direction inverse residual transform circuit accesses the transpose buffer to retrieve the intermediate inverse residual transform result, and processes the intermediate inverse residual transform result to generate a final inverse residual transform result, where the final inverse residual transform result of the inverse second transform is further processed by an inverse transform circuit.

Abstract: Techniques are described for coding residual data of a prediction residual block in either a lossy or lossless coding mode, in which a transform is skipped or bypassed. The techniques of this disclosure include determining whether to reposition, e.g., rotate or flip, residual data of a residual block prior to coding the residual data of the residual block. For both the lossy and lossless coding modes, a video coding device determines whether to reposition residual data of a residual block based on a prediction mode of the residual block and a size of the residual block. In some examples, the techniques disable repositioning for all residual blocks in the inter-prediction mode and the intra block copying prediction mode, and determine to reposition residual blocks in the intra-prediction mode when the residual blocks have block sizes that are less than or equal to a threshold size.

Abstract: An image coding method includes: generating a predicted block; calculating a residual block; calculating quantized coefficients by performing transform and quantization on the residual block; calculating a coded residual block by performing inverse quantization and inverse transform on the quantized coefficients; generating a temporary coded block; determining whether or not an offset process is required, to generate first flag information indicating a result of the determination; executing the offset process on the temporary coded block when it is determined that the offset process is required; and performing variable-length coding on the quantized coefficients and the first flag information.