A method implemented by a video coding apparatus includes applying a neural network (NN) filter to an unfiltered sample of a video unit to generate a filtered sample, where the NN filter is based on a first NN filter model having a first depth, or a second NN filter model having a second depth, where the depth comprises a number of residual blocks of the respective NN filter model, and where the second depth is different than the first depth. The method also includes performing a conversion between a video media file and a bitstream based on the filtered sample.

There is disclosed an encoder, a decoder, related methods, and non-transitory storage units storing instructions which, when executed by a computer, cause the computer to perform the methods.

At an encoder (300), after a spatial transformation stage (304), there is obtained a spatially transformed version (306) of input image information (302) having multiple bands and, for each band, multiple transform band coefficients. After the generation of precincts (311), each comprising transform coefficients covering a predetermined spatial area of the input image information (302), there is provided a component transformation stage (320, 325), to apply one component transformation (CTr) selected (327) out of a plurality of predetermined component transformations, to each band (102′) of each precinct (311). Hence, there is obtained a spatially transformed and color transformed version (323) of the input image information (302), which is subsequently quantized and entropy encoded.

There is disclosed an encoder, a decoder, related methods, and non-transitory storage units storing instructions which, when executed by a computer, cause the computer to perform the methods.

At an encoder (300), after a spatial transformation stage (304), there is obtained a spatially transformed version (306) of input image information (302) having multiple bands and, for each band, multiple transform band coefficients. After the generation of precincts (311), each comprising transform coefficients covering a predetermined spatial area of the input image information (302), there is provided a component transformation stage (320, 325), to apply one component transformation (CTr) selected (327) out of a plurality of predetermined component transformations, to each band (102′) of each precinct (311). Hence, there is obtained a spatially transformed and color transformed version (323) of the input image information (302), which is subsequently quantized and entropy encoded.

An apparatus for decoding a sequence of pictures from a data stream is configured for decoding a picture of the sequence by deriving a residual transform signal of the picture from the data stream; combining a residual transform signal with a buffered transform signal approximation of a previous picture of the sequence so as to obtain a transform signal representing the picture, the transform signal comprising a plurality of transform coefficients; and subjecting the transform signal to a spectral-to-spatial transformation. The apparatus is configured for deriving the buffered transform signal approximation from a further transform signal representing the previous picture so that the buffered transform signal approximation comprises approximations of further transform coefficients of the further transform signal.

An apparatus for decoding a sequence of pictures from a data stream is configured for decoding a picture of the sequence by deriving a residual transform signal of the picture from the data stream; combining a residual transform signal with a buffered transform signal approximation of a previous picture of the sequence so as to obtain a transform signal representing the picture, the transform signal comprising a plurality of transform coefficients; and subjecting the transform signal to a spectral-to-spatial transformation. The apparatus is configured for deriving the buffered transform signal approximation from a further transform signal representing the previous picture so that the buffered transform signal approximation comprises approximations of further transform coefficients of the further transform signal.

A method of video decoding can include receiving a bit stream including coded bits of bins of syntax elements. The syntax elements are of various types that correspond to transform coefficients of a transform block in a coded picture. Context modeling is performed to determine a context model for each bin of the syntax elements. In a given frequency region of the transform block, for one type of the syntax elements, a group of the transform coefficients having different template magnitudes within a predetermined range share a same context model, or one of the transform coefficients uses the same context model for possible different template magnitudes of the one of the transform coefficients. The possible different template magnitudes are within the predetermined range. The coded bits are decoded based on the context models determined for each bin of the syntax elements to determine the bins of the syntax elements.

A method of video decoding can include receiving a bit stream including coded bits of bins of syntax elements. The syntax elements are of various types that correspond to transform coefficients of a transform block in a coded picture. Context modeling is performed to determine a context model for each bin of the syntax elements. In a given frequency region of the transform block, for one type of the syntax elements, a group of the transform coefficients having different template magnitudes within a predetermined range share a same context model, or one of the transform coefficients uses the same context model for possible different template magnitudes of the one of the transform coefficients. The possible different template magnitudes are within the predetermined range. The coded bits are decoded based on the context models determined for each bin of the syntax elements to determine the bins of the syntax elements.

An image decoding method performed by a decoding device, according to the present document, comprises the steps of: receiving a bitstream including residual information of a current block; deriving a specific number of context-encoding bins for context syntax elements for a current sub-block of the current block; decoding the context syntax elements for the current sub-block included in the residual information on the basis of the specific number; deriving transform coefficients for the current sub-block on the basis of the decoded context syntax elements; deriving residual samples for the current block on the basis of the transform coefficients; and generating a reconstructed picture on the basis of the residual samples.

An image decoding method performed by a decoding device, according to the present document, comprises the steps of: receiving a bitstream including residual information of a current block; deriving a specific number of context-encoding bins for context syntax elements for a current sub-block of the current block; decoding the context syntax elements for the current sub-block included in the residual information on the basis of the specific number; deriving transform coefficients for the current sub-block on the basis of the decoded context syntax elements; deriving residual samples for the current block on the basis of the transform coefficients; and generating a reconstructed picture on the basis of the residual samples.

Disclosed decoding method of the intra prediction mode comprises the steps of: determining whether an intra prediction mode of a present prediction unit is the same as a first candidate intra prediction mode or as a second candidate intra prediction mode on the basis of 1-bit information; and determining, among said first candidate intra prediction mode and said second candidate intra prediction mode, which candidate intra prediction mode is the same as the intra prediction mode of said present prediction unit on the basis of additional 1-bit information, if the intra prediction mode of the present prediction unit is the same as at least either the first candidate intra prediction mode or the second candidate intra prediction mode, and decoding the intra prediction mode of the present prediction unit.