Abstract: A refined reconstruction block of a first color component in a picture is determined by at least one of clipping and bilateral filtering a sum of a prediction block of the first color component and a residual of the first color component. A residual block of a second color component is predicted from the refined 5 construction block of the first color component. Applying clipping and/or filtering to the first color component prior to using it in cross-component prediction of the second color component improves and refines predictions or residuals of another color component.

Abstract: A pixel value of a pixel in a picture of a video sequence is modified by a weighted combination of the pixel value and at least one spatially neighboring pixel value in a filtering. The filtering depends on a pixel distance between the pixel and a neighboring pixel and on a pixel value difference between the pixel and a neighboring pixel value of the neighboring pixel. The filtering is controlled by a spatial parameter and a range parameter. The spatial parameter depends on at least one of a width and a height of a transform block, and on at least one of a prediction type of a block of pixels in the picture, a picture type of the picture, and a slice type of a slice in the picture.

Abstract: A method for encoding or decoding an image of a video sequence is provided. The method comprises obtaining a set of sample values associated with the image. The method comprises determining a relative location of the current sample value with respect to a virtual boundary. The virtual boundary is defined with respect to a block boundary between the first block of sample values and a second block of sample values. The virtual boundary is parallel with the block boundary and separated from the block boundary by at least one row or column of sample values included in the first block of sample values. The method comprises a filter strength value based on the determined relative location of the current sample value with respect to the virtual boundary. The method comprises filtering the current sample value based on the selected filter strength value.

Abstract: A deblocking the method. The method includes deblocking a block boundary between a first block, B1, and a second block, B2, with the restriction that not more than 5 samples are modified on the B2 side of the block boundary as a result of the deblocking. The deblocking method also includes deblocking a sub-block boundary within the B2 block such that not more than 2 samples on the side of the sub-block boundary within the B2 block that is closest to the block boundary between B1 and B2 are modified by the deblocking.

Abstract: A method of encoding/decoding a picture of a video signal includes selecting a block of the picture for decoding, comparing a motion vector associated with the selected block to a motion vector associated with a neighbouring block that is adjacent the block, and determining whether to use motion vectors associated with the neighbouring block in encoding/decoding of the block based on the comparison of the motion vector associated with the selected block and the motion vector associated with the neighbouring block.

Abstract: A method of decoding a block of video samples from a video bitstream is provided in which the method includes decoding a DQPRP value, deriving a PQP value for a block having a non-zero residual, decoding a DDQP value for the block, deriving a SDQP value for the block from the DDQP value and the DQPRP value, deriving a block QP value for the block from the SDQP value and the PQP value, decoding at least one non-zero coefficient of the block, deriving values of a residual block for the block by first scaling the at least one non-zero coefficient using the QP value and thereafter applying an inverse transform, deriving values of a prediction block spatial or temporal prediction, and deriving decoded sample values for the block by adding the values of the residual block and the values of the prediction block.

Abstract: A deblocking method for deblocking a boundary between a first block of samples, block P, and a second block of samples, block Q. The method includes determining whether at least one of the P block or the Q block is a combined intra-inter prediction block; and, as a result of determining that at least one of the P block or the Q block is a combined intra-inter prediction block, deblocking the boundary between the P block and the Q block.

Abstract: A processing for a first pixel in a picture comprises obtaining a lower limit of a first color component of the first pixel in a first color space based on a distance between a color of the first pixel and a first distorted version of the color in a second color space. An upper limit of the first color component in the first color 5 space is obtained based on a distance between the color and a second distorted version of the color in the second color space. A filtered value is obtained of the first color component and which is equal to or larger than the lower limit and equal to or lower than the upper limit. The processing results in filtered values that are cheaper to encode but that are visibly undistinguishable from the original colors of the pixels.

Abstract: There are provided mechanisms for temporal motion vector prediction of a current picture in a series of pictures of a video sequence. The method comprises determining, for a current block of the current picture, whether any one of: left, top, top-right and left-bottom spatial neighboring blocks of the current block in the current picture uses a collocated picture as a reference picture. The method further comprises, when the determination is that one of the left, top, top-right and left-bottom spatial neighboring block uses a collocated picture as a reference picture, using a motion vector of the one of the spatial neighboring blocks as a temporal vector of the current block.

Abstract: A method of decoding a block of video samples from a video bitstream is provided in which the method includes decoding a DQPRP value, deriving a PQP value for a block having a non-zero residual, decoding a DDQP value for the block, deriving a SDQP value for the block from the DDQP value and the DQPRP value, deriving a block QP value for the block from the SDQP value and the PQP value, decoding at least one non-zero coefficient of the block, deriving values of a residual block for the block by first scaling the at least one non-zero coefficient using the QP value and thereafter applying an inverse transform, deriving values of a prediction block spatial or temporal prediction, and deriving decoded sample values for the block by adding the values of the residual block and the values of the prediction block.

Abstract: A pixel pre-processing comprises subsampling a linear color in a first color space to obtain a subsampled linear color in the first color space. A first transfer function is applied to the subsampled linear color the first color space to obtain a subsampled non-linear color in the first color space. A first color transform is applied to the subsampled non-linear color in the first color space to obtain a subsampled first non-linear chroma component value and/or a subsampled second non-linear chroma component value in a second color space. A non-linear luma component value in the second color space is derived for the pixel, which together with the subsampled non-linear chroma component values represent a color the pixel. The pre-processing reduces chroma artifacts that may otherwise occur when chroma subsampling is performed following application of the first transfer function and the first color transform.

Abstract: The present invention relates to an encoder, transcoder and methods thereof. A transcoder embodiment involves transcoding a bitstream representing an original video source from an input video format to an output video format. An encoder embodiment involves providing transform coefficients in side information related to an encoded video bitstream.

Abstract: An asymmetric deblocking method for deblocking a boundary between a P block and a Q block such that 5 samples within the P block and 7 or 3 samples within the Q block are modified. The method includes determining a value refP based on at least p5, determining a value refQ based on at least qx, wherein qx is q3 or q7; determining a value refMiddle based on at least p0 and q0, wherein p0 is directly adjacent to the boundary and q0 is directly adjacent to the boundary; performing a linear interpolation between refP and refMiddle; and performing a linear interpolation between refQ and refMiddle.

Abstract: An encoded video sequence including a plurality of images may be decoded. First and second adjacent blocks of an image of an encoded video sequence may be provided. A line of pixels including pixels of the first and second blocks may be defined extending across a boundary between the first and second blocks. A first reference value may be calculated based on a first pixel of the pixels from the first block. A second reference value may be calculated based on a second pixel of the pixels from the second block. Filtered pixel values for each pixel of the line of pixels between the first pixel and the second pixel may be calculated using interpolation based on the first and/or second reference values. Filtered blocks may be generated using the filtered pixel values, and a decoded video sequence may be generated based on the filtered blocks.

Abstract: A method of reducing blocking artifacts associated with pixels of a block boundary of an image. Pixel values of pixels from a first block and a neighboring block, being located on opposite sides of a block boundary, are evaluated. A first offset for the two pixels of each block located next to the block boundary is calculated, after which the first offset is compared to a first threshold value. If abs[first offset]<first threshold, the pixel values of consecutive pixels from the first block and the pixel values of consecutive pixels from the second block are modified by applying normal filtering on the respective pixels, while if instead abs[first offset]>=first threshold, the pixel values of consecutive pixels from the first block and the pixel values of consecutive pixels from the second block are modified by applying weak filtering or no filtering at all on the respective pixels.

Abstract: A deblocking filtering control involves deciding whether to apply deblocking filtering to sample values in a sample block in a picture and in a neighboring sample block in the picture based on i) a first magnitude modification of sample prediction values in a first prediction block in a reference picture for the sample block and ii) a second magnitude modification of sample prediction values in a second prediction block in the reference picture for the neighboring sample block. The sample block and the neighboring sample block are separated in the picture by a block boundary. This decision to apply deblocking filtering based on magnitude modifications reduce blocking artefacts that may otherwise arise in certain pictures of a video sequence.

Abstract: A method of encoding a pixel comprises encoding second and third color component values of the pixel in a first color space. A first color component value in a second color space is obtained for the pixel. A first color component value in the first color space is determined based on minimizing an error computed based on a difference between the first color component value in the second color space and a test color component value in the second color space derived based on the encoded second and third color component values. The first color component value in the first color space is then encoded. The target value for coding of the first color component is thereby adapted given encoding of the second and third color components. As a result the visual quality of the pixel is improved.

Abstract: According to one aspect the present invention relates to a method for a video encoder. The method comprises providing (601) to a transcoder a first bitstream representing a video sequence with a first format, creating (602) a second bitstream representing transcoding information indicative of a transcoding method that should be used by the transcoder for transcoding the video sequence from the first format to a second format, and providing (603) to the transcoder the second bitstream.

Abstract: A method of reducing blocking artifacts associated with pixels of a block boundary of an image. Pixel values of pixels from a first block and a neighboring block, being located on opposite sides of a block boundary, are evaluated. A first offset for the two pixels of each block located next to the block boundary is calculated, after which the first offset is compared to a first threshold value. If abs[first offset]<first threshold, the pixel values of consecutive pixels from the first block and the pixel values of consecutive pixels from the second block are modified by applying normal filtering on the respective pixels, while if instead abs[first offset]>=first threshold, the pixel values of consecutive pixels from the first block and the pixel values of consecutive pixels from the second block are modified by applying weak filtering or no filtering at all on the respective pixels.

Abstract: A method of encoding/decoding a picture of a video signal includes selecting a block of the picture for decoding, comparing a motion vector associated with the selected block to a motion vector associated with a neighbouring block that is adjacent the block, and determining whether to use motion vectors associated with the neighbouring block in encoding/decoding of the block based on the comparison of the motion vector associated with the selected block and the motion vector associated with the neighbouring block.