摘要:
A motion vector calculation method which attains a higher compression rate, includes: a selection step of selecting one of at least one reference motion vector of a reference block; and a calculation step of calculating a motion vector of a current block to be processed, using the one reference motion vector selected in the selection step, and in the selection step, when the reference block has two reference motion vectors, one of the two reference motion vectors is selected based on whether the reference block is located before or after the current block in display time order, and when the reference block has only one reference motion vector, the one reference motion vector is selected.
摘要:
An image coding method for coding an input image per block to generate a coded image signal includes: predicting for each prediction unit which is an area obtained by partitioning a target block to generate a prediction image of the target block; comparing a transform unit which is an area obtained by partitioning the target block and is a processing unit for frequency transform with the prediction unit, to detect part of a boundary of the prediction unit, the boundary being located within the transform unit; performing boundary filtering on the detected part of the boundary in the generated prediction image; calculating a difference between a filtered prediction image and the input image to generate a difference image of the target block; and performing frequency transform on the difference image for each transform unit.
摘要:
The image decoding method includes: determining a context for use in a current block to be processed, from among a plurality of contexts; and performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context, wherein in the determining: the context is determined under a condition that control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and the context is determined under a condition that the control parameter of the upper block is not used, when the signal type is a second type, and the second type is “intra_chroma_pred_mode”.
摘要:
The image decoding method includes: determining a context for use in a current block to be processed, from among a plurality of contexts; and performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context, wherein in the determining: the context is determined under a condition that control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and the context is determined under a condition that the control parameter of the upper block is not used, when the signal type is a second type.
摘要:
A coding method comprises: transforming an input signal; quantizing a transformed output signal; and entropy coding quantized coefficients, wherein the transforming includes: generating a first transformed output signal by performing a first transform on the input signal using a first transform coefficient; and generating a second transformed output signal by performing, using a second transform coefficient, a second transform on a first partial signal which is a part of the first transformed output signal, and outputting the transformed output signal including the generated second transformed output signal and a second partial signal which is the remaining part of the first transformed output signal other than the first partial signal, and wherein, in the generating and outputting, at least one of (i) the first partial signal that is a target signal range for the second transform and (ii) the second transform coefficient is adaptively determined temporally or spatially.
摘要:
The coding method includes: transforming pixel values of an image into a two-dimensional matrix including N coefficients in a frequency domain; quantizing the N coefficients to generate N quantized coefficients; generating a one-dimensional sequence based on the two-dimensional matrix and tree structure information that defines a binary tree; and coding the one-dimensional sequence and at least some of the N quantized coefficients. The generating includes: determining, based on the two-dimensional matrix, a reference destination information item indicating positions of the N quantized coefficients in the two-dimensional matrix to be referenced to by the N leaf nodes, respectively (S31); assigning one of a first value and a second value to each of the nodes of the binary tree, based on the two-dimensional matrix and the reference destination information item (S32); and arranging, in preorder, the values assigned to the respective nodes to generate the one-dimensional sequence (S33).
摘要:
The image decoding method includes determining a context for use in a current block to be processed, from among a plurality of contexts, wherein in the determining: the context is determined under a condition that control parameters of a left block and an upper block are used, when the signal type is a first type; and the context is determined under a third condition that the control parameter of the upper block is not used and a hierarchical depth of a data unit to which the control parameter of the current block belongs is used, when the signal type is a third type, and the third type is one or more of (i) “merge_flag”, (ii) “ref_idx_l0” or “ref_idx_l1”, (iii) “inter_pred_flag”, (iv) “mvd_l0” or “mvd_l1”, (v) “intra_chroma_pred_mode”, (vi) “cbf_luma”, and (vii) “cbf_cb” or “cbf_cr”.
摘要:
An arithmetic decoding method is a method in which a context variable specifying a probability of a possible value of each of elements included in a binary string corresponding to a value of a given variable is initialized and arithmetic decoding is performed, using the context variable. The method includes: determining, from among a plurality of initialization methods as a method of initializing the context variable, an initialization method corresponding to the given variable or a group which includes the given variable; and initializing the context variable using the determined initialization method.
摘要:
An image coding method for performing compression-coding on image data includes: binarizing a signal to be coded of the image data, to generate a binary signal; determining a low-order context which is a context associated with a type of the signal to be coded, and a high-order context that is common to the low-order context and a context associated with another type; calculating coding probability information to be used in arithmetic coding of the binary signal, using (i) high-order probability information corresponding to the determined high-order context and (ii) low-order probability information corresponding to the determined low-order context; performing the arithmetic coding on the binary signal using the coding probability information; and updating the high-order probability information and the low-order probability information based on the binary signal.
摘要:
The image decoding method includes: determining a context for use in a current block to be processed, from among a plurality of contexts; and performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context, wherein in the determining: the context is determined under a condition that control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and the context is determined under a condition that the control parameter of the upper block is not used, when the signal type is a second type, and the second type is one of “mvd_l0” and “mvd_l1”.