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 in 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: 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: It is presented a method for applying a filter on at least one colour component of an input signal used for video processing. The method is performed in a filter device and comprises the steps of: converting the input signal, by applying a first conversion process, to a modified signal, wherein both the input signal and the modified signal are in a spatial domain; filtering the modified signal with a filter, yielding a filtered signal; and converting the filtered signal, by applying a second conversion process, to an output signal, wherein the output signal is in a spatial domain.

Abstract: A first filter decision value is calculated for a block of pixels in a video frame based on pixel values of pixels in a first line of pixels in the block. A second filter decision value is also calculated for the block based on pixel values of pixels in a corresponding first line of pixels in a neighboring block in the video frame. The first filter decision value is used to determine how many pixels in a line of pixels in the block to filter relative to a block boundary between the block and the neighboring block. The second filter decision value is used to determine how many pixels in a corresponding line of pixels in the neighboring block to filter relative to the block boundary.

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: The present invention relates to a method and a transcoder arrangement of transcoding a bitstream representing an original video source from an input format to an output format. The method comprises the steps of receiving (S10) the bitstream with the input video format, wherein the input video format is a high fidelity format; and receiving (S20) side information related to said video bitstream. Said side information comprising at least: a video bitstream representing the original video source with a low fidelity input video format, coding parameters optimized based on knowledge of the original video source; transform coefficients, indicative of a residual between the original video source and a decoded version of the high fidelity format.

Abstract: A method of processing pixels in a picture of a video sequence comprising multiple pictures comprises identifying a pixel to be processed in the picture for which a variation in a linear representation of a color of the pixel that is smaller than a first threshold value results in a variation in a non-linear representation of the color that is larger than a second threshold value. The variation in the linear representation of the color also results in a variation in a luminance and chrominance based representation of the color that is smaller than a third threshold value. The method also comprises processing the identified pixel by modifying a value of at least one color component of the pixel. The method achieves a selective denoising of particular color components in certain situations to reduce the encoding cost yet do not significantly affect the visual quality.

Abstract: A method is disclosed performed in an encoder for encoding video pictures into a video bit stream, the method comprising: obtaining a denoised version of a reference picture; performing a matching procedure at least once, the matching procedure comprising matching a reference matching area of the reference picture to a matching area of a second picture and matching a reference matching area of the denoised version to the matching area of the second picture, and encoding a block of a current picture by selecting, for the block, a first prediction area based on a first reference area of the reference picture or a second prediction area based on a second reference area of the denoised version, wherein the prediction area having lowest matching error to the corresponding matching area of the second picture is selected. A corresponding method in a decoder is disclosed, and encoder, decoder, computer programs and computer program products.

Abstract: In a motion estimation for a group of at least one image element in a frame of a video sequence, a global motion is determined between the frame and a reference frame. Uncovered groups present in an uncovered region of the frame are identified based on the determined global motion. The global motion is assigned as motion representation for these identified uncovered groups. The assigned motion representation is useful for constructing new frames in the sequence in a frame rate up-conversion.

Abstract: Blocking artifacts at a block boundary between a block and a neighboring block in a video frame are reduced by calculating an offset based on pixel values of pixels in a line of pixels in the block and based on pixel values of pixels in a corresponding line of pixels in the neighboring block. The offset is added to the pixel value of the pixel closest to the block boundary in the line of pixels and is subtracted from the pixel value of the pixel closest to the block boundary in the corresponding line of pixels. The resulting deblocking filter has good low-pass characteristics and is efficient for reducing blocking artifact.

Abstract: Video encoder and decoder and methods therein for transform skipped encoding and decoding of blocks of pixels. The methods comprise a modified use of an existing context model associated with transform coefficients, for deriving contexts for a bitmask indicating which residual values (i.e., not transform coefficients), in a transform skipped residual block, that are greater than one. The methods are applicable to video coding schemes such as HEVC.

Abstract: There are provided mechanisms for encoding a picture of a video sequence into a video bitstream. The picture comprises at least a first color component and a second color component. The first color component comprises a first block of samples and the second color component comprises a second block of samples. A method comprises segmenting the first block of samples and the second block of samples into at least a first segment and a second segment so that samples with the same positions in the first block and the second block belong to the same segment. The method comprises predicting sample values in the second block of samples based on the sample values in the first block of samples that belong to the same segment.

Abstract: A first filter decision value is calculated for a block of pixels in a video frame based on pixel values of pixels in a first line of pixels in the block. A second filter decision value is also calculated for the block based on pixel values of pixels in a corresponding first line of pixels in a neighboring block in the video frame. The first filter decision value is used to determine how many pixels in a line of pixels in the block to filter relative to a block boundary between the block and the neighboring block. The second filter decision value is used to determine how many pixels in a corresponding line of pixels in the neighboring block to filter relative to the block boundary.

Abstract: Reconstructed prediction errors in a sub-portion (12) of a residual block (11) obtained by inverse transforming a transform block (10) are modified in order to spatially improve localized portions of the residual block (11), e.g. to compensate for visual artifacts from transform coding. The modification affects reconstructed prediction errors in the sub-portion (12) of the residual block (11) but not reconstructed prediction errors in a remaining portion of the residual block (11).

Abstract: It is presented a method for encoding a video frame of a piece of video content. The method is performed in an encoder device and comprises the steps of: dividing the video frame into a set of non-overlapping regions, wherein the set comprises at least one region; assigning each region, in the set of regions, to a separate processing unit; encoding, in each processing unit, picture data of the respective region; collecting progress data from each processing unit, the progress data indicating progress of the encoding of the respective region; and dividing a particular region into a plurality of smaller regions and assigning each smaller region to a separate processing unit, when the progress data indicates that progress of encoding the particular region is insufficient.

Abstract: Blocking artifacts at a block boundary between a block and a neighboring block in a video frame are reduced by calculating an offset based on pixel values of pixels in a line of pixels in the block and based on pixel values of pixels in a corresponding line of pixels in the neighboring block. The offset is added to the pixel value of the pixel closest to the block boundary in the line of pixels and is subtracted from the pixel value of the pixel closest to the block boundary in the corresponding line of pixels. The resulting deblocking filter has good low-pass characteristics and is efficient for reducing blocking artifact.

Abstract: A method (20) is disclosed performed in an encoder (40) for encoding video pictures into a video bit stream, the method (20) comprising: obtaining (21) a transformed version (2?; 12?, 13?) of a reference picture (2; 12, 13), by using a geometric transformation comprising at least one of: scaling, rotation, shearing, reflection, and projection; performing (22) a matching procedure at least once, the matching procedure comprising matching a reference matching area (6; 15, 16) of the reference picture (2; 12, 13) to a matching area (4; 16, 15) of a second picture (1; 13, 12) and matching a reference matching area (6?; 15?, 16?) of the transformed version (2?; 12?, 13?) to the matching area (4; 16, 15) of the second picture (1; 13, 12); and encoding (23) a block (3; 14) of the current picture (1; 11) by selecting for the block (3; 14) a first prediction area (5; 15, 16) based on the reference matching area (6; 15, 16) or a second prediction area (5?; 15?, 16?) based on the transformed reference matching area (6?;

Abstract: Video encoder and decoder and methods therein for transform skipped encoding and decoding of blocks of pixels. The methods comprise a modified use of an existing context model associated with transform coefficients, for deriving contexts for a bitmask indicating which residual values (i.e., not transform coefficients), in a transform skipped residual block, that are greater than one. The methods are applicable to video coding schemes such as HEVC.

Abstract: A first filter decision value is calculated for a block (10) of pixels (11, 13, 15, 17) in a video frame based on pixel values of pixels (11, 13, 15) in a first line (12) of pixels (11, 13, 15, 17) in the block (10). A second filter decision value is also calculated for the block (10) based on pixel values of pixels (21, 23, 25, 27) in a corresponding first line (22) of pixels (21, 23, 25, 27) in a neighboring block (20) in the video frame. The first filter decision value is used to determine how many pixels in a line (12) of pixels (11, 13, 15, 17) in the block (10) to filter relative to a block boundary (1) between the block (10) and the neighboring block (20). The second filter decision value is used to determine how many pixels in a corresponding line (22) of pixels (21, 23, 25, 27) in the neighboring block to filter relative to the block boundary (1).

Abstract: Video encoder and decoder and methods therein for transform skipped encoding and decoding of blocks of pixels. The methods comprises a modified use of an existing context model associated with transform coefficients, for deriving contexts for a bitmask indicating which residual values (i.e. not transform coefficients), in a transform skipped residual block, that are greater than one. The methods are applicable to video coding schemes such as HEVC.