Quantization matrix can be used to adjust quantization of transform coefficients at different frequencies. In one embodiment, a single fixed parametric model, such as a polynomial is used to represent a quantization matrix. Modulation of bit cost and complexity is achieved by specifying only the n first polynomial coefficients, the remaining ones being implicitly set to zero or other default values. One form of the single fixed polynomial is a fully developed polynomial in (x,y), where x,y indicate the coordinates of a given coefficient in a quantization matrix, with terms ordered by increasing exponent. Since higher exponents are the last ones, reducing the number of polynomial coefficients reduces the degree of the polynomial, hence its complexity. The polynomial coefficients can be symmetrical in x and y, and thus reducing the number of polynomial coefficients that need to be signaled in the bitstream.

According to an embodiment of the present invention, a picture decoding method performed by a decoding apparatus is provided. The method comprises: decoding image information comprising information on a quantization parameter (QP), deriving an expected average luma value of a current block from neighboring available samples, deriving a quantization parameter offset (QP offset) for deriving a luma quantization parameter (luma QP) based on the expected average luma value and the information on the QP, deriving the luma QP based on the QP offset, performing an inverse quantization for a quantization group comprising the current block based on the derived luma QP, generating residual samples for the current block based on the inverse quantization, generating prediction samples for the current block based on the image information and generating reconstructed samples for the current block based on the residual samples for the current block and the prediction samples for the current block.

Video processing methods and apparatuses for processing a current block in a current picture by reference picture resampling include receiving input data of the current block, determining a scaling window of the current picture and a scaling window of a reference picture. The current picture and reference picture may have different scaling window sizes. A ratio between a scaling window width, height, or size of the current picture and a scaling window width, height, or size of the reference picture is constrained to be within a ratio constraint. A reference block is generated from the reference picture according to the ratio, and used to encode or decode the current block.

Video processing methods and apparatuses for processing a current block in a current picture by reference picture resampling include receiving input data of the current block, determining a scaling window of the current picture and a scaling window of a reference picture. The current picture and reference picture may have different scaling window sizes. A ratio between a scaling window width, height, or size of the current picture and a scaling window width, height, or size of the reference picture is constrained to be within a ratio constraint. A reference block is generated from the reference picture according to the ratio, and used to encode or decode the current block.

A method of encoding an image into a coded image, the method comprising: writing a quantization offset parameter into the coded image, determining a prediction mode type for coding a block of image samples of the image into a coding unit of the coded image, determining a quantization parameter for the block of image samples, and determining if the prediction mode type is of a predetermined type, wherein if the prediction mode type is of the predetermined type, the method further comprises: modifying the determined quantization parameter using the quantization offset parameter, and performing a quantization process for the block of image samples using the modified quantization parameter, and wherein if the prediction mode type is not of the predetermined type, the method further comprises: performing a quantization process for the block of image samples using the determined quantization parameter.

A method of encoding an image into a coded image, the method comprising: writing a quantization offset parameter into the coded image, determining a prediction mode type for coding a block of image samples of the image into a coding unit of the coded image, determining a quantization parameter for the block of image samples, and determining if the prediction mode type is of a predetermined type, wherein if the prediction mode type is of the predetermined type, the method further comprises: modifying the determined quantization parameter using the quantization offset parameter, and performing a quantization process for the block of image samples using the modified quantization parameter, and wherein if the prediction mode type is not of the predetermined type, the method further comprises: performing a quantization process for the block of image samples using the determined quantization parameter.

A moving picture decoding apparatus, method, and medium for decoding a current block are provided. A first candidate is derived from a first motion vector that has been used to decode a first block. The first block is adjacent to the current block. A first index identifying a reference picture to be selected for decoding the current block is decoded. A second candidate having a second motion vector that includes a non-zero value is derived. The non-zero value is assigned to the reference picture. A selected candidate is selected from a plurality of candidates, including the first candidate and the second candidate. A second index identifying the selected candidate is decoded. The current block is decoded using the selected candidate. The second candidate includes the non-zero value of the reference picture, with the reference picture being selected from a plurality of referable reference pictures.

A method to be performed by a receiving apparatus for decoding an encoded bitstream representing a sequence of pictures of a video stream is provided. In the method, capabilities relating to level of decoding parallelism for the decoder are identified, a parameter indicative of the decoder's capabilities relating to level of decoding parallelism is kept, and for a set of levels of decoding parallelism, information relating to HEVC profile and HEVC level that the decoder is capable of decoding is kept. A method for encoding a bitstream representing a sequence of pictures of a video stream is also provided. In the method, a parameter is received from a transmitting apparatus that should decode the encoded bitstream.

A method to be performed by a receiving apparatus for decoding an encoded bitstream representing a sequence of pictures of a video stream is provided. In the method, capabilities relating to level of decoding parallelism for the decoder are identified, a parameter indicative of the decoder's capabilities relating to level of decoding parallelism is kept, and for a set of levels of decoding parallelism, information relating to HEVC profile and HEVC level that the decoder is capable of decoding is kept. A method for encoding a bitstream representing a sequence of pictures of a video stream is also provided. In the method, a parameter is received from a transmitting apparatus that should decode the encoded bitstream.

Predicting a component of a current pixel belonging to a current sub-aperture image in a matrix of sub-aperture images captured by a sensor of a type I plenoptic camera can involve, first, determining a location on the sensor based on: a distance from an exit pupil of a main lens of the camera to a micro-lens array of the camera; a focal length of the main lens; a focal length of the micro-lenses of the micro-lens array; and a set of parameters of a model of the camera allowing for a derivation of a two-plane parameterization describing the field of rays corresponding to the pixels of the sensor; and, second, predicting the component based on one reference pixel belonging to a reference sub-aperture image in the matrix and located on the sensor in a neighborhood of the location.