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: A processing of pixels comprises checking whether a color component of a pixel in a color space resulting in a smallest error between at least one color component in another color space determined based on the color component and at least one original color component of the pixel in the another color space causes any color channel of the pixel to fall outside of an allowed range. A value of the color component is obtained using a first function/LUT if the color component resulting in the smallest error does not cause any color channel of the pixel to fall outside of said allowed range. However, a value of the color component is obtained using a second, different function/LUT if the color component resulting in the smallest error causes any color channel of the pixel to fall outside of the allowed range.

Abstract: An example method includes receiving a video bitstream with a high fidelity input format and side information related to the video bitstream. The side information includes a video bitstream representing the original video source with a low fidelity input 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. The method further includes decoding the side information to generate transcoding guiding information, estimating a representation of video bitstream with a low fidelity output format, based on the received bit stream and the generated transcoding guiding information, improving the estimated low-fidelity representation by adding the transform coefficients of the side information to transform coefficients generated from the estimated low-fidelity representation, and encoding the improved estimated representation of the low-fidelity bitstream.

Abstract: Visible artifacts in a video stream of pictures with slices are reduced by having a separate maximum transform size for intra coding units in inter coded slices as compared to intra coding units in intra coded slices and/or inter coding units or by penalizing the usage of large transform size for such intra coding units in inter coded slices as compared to intra coding units in intra coded slices and/or inter coding units.

Abstract: In a method of transcoding of a video bitstream by a transcoder arrangement, performing the steps of receiving (S10) a video bitstream with a predetermined input video format, receiving (S20) side information related to the video bitstream, the side information comprising at least one of mode or motion or in-loop filter information relating to at least one other predetermined video format for the video bitstream. Further, performing the steps of decoding (S40) the received side information to generate transcoding guiding information, and encoding (S50) a representation of the received video bitstream based at least on the generated transcoding guiding information, to provide a transcoded video bitstream with a predetermined output video format.

Abstract: A pre-processing of a pixel in a picture comprises determining, based on a minimum color component value for the pixel, whether a default processing chain is used to derive a luma component value, a first subsampled chroma component value and a second subsampled chroma component value or whether an auxiliary processing chain is used to derive at least one of the luma component value, the first subsampled chroma component value and the second subsampled chroma component value. The pre-processing improves the visual quality of pictures but at a low cost with regard to extra processing time.

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: One exemplary embodiment presents a method of decoding a group of image elements in a frame of an encoded video sequence. The method comprises determining an intra-prediction mode for the group of image elements, and providing a first prediction of the group of image elements according to the determined intra-prediction mode. The method further comprises determining a location identifier identifying a location of a decoded version of another group of image elements in a frame of the video sequence, and providing a second prediction of the group of image elements using the determined location identifier.

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: In a method of transcoding of a video bitstream by a transcoder arrangement, performing the steps of receiving a video bitstream with a predetermined input video format, receiving side information related to the video bitstream, the side information comprising at least one of mode or motion or in-loop filter information relating to at least one other predetermined video format for the video bitstream. Further, performing the steps of decoding the received side information to generate transcoding guiding information, and encoding a representation of the received video bitstream based at least on the generated transcoding guiding information, to provide a transcoded video bitstream with a predetermined output video format.

Abstract: There are provided mechanisms for encoding a picture of a video sequence in a video bitstream. The picture comprises a first block of samples, wherein each sample in the first block of samples has sample values associated with at least a luma color component and a chroma color component. Each color component is assigned a first quantization parameter. The method comprises calculating a quantization parameter change for at least one color component in the first block of samples, with respect to the first quantization parameter, based on statistics calculated from the sample values from at least one color component in a second block of samples. The second block of samples is one of: source samples of the first block of samples and source samples larger than the first block of samples including the first block of samples.

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: There are provided mechanisms for encoding a picture of a video sequence in a video bitstream. The picture comprises pixels wherein each pixel has a color value comprising at least one color component value. The method comprises determining a frequency distribution of the color component values of the at least one color component. The method comprises determining at least one quantization parameter for coding of transform coefficients for the at least one color component based on the determined frequency distribution of the color component values. The method comprises encoding the determined at least one quantization parameter.

Abstract: A QP offset value is calculated for a chroma component of a pixel in a picture of a video sequence based on a reference QP value and a factor that depends on a difference between a capture color space for the pixel and an encoded color space for the pixel. A QP value is then calculated for the chroma component based on the reference QP value reduced by the QP off-set value. The calculation of QP values for chroma components based on the factor that depends on the difference between capture and encoded color spaces improves the chroma quality in an efficient way in particular for HDR and WCG video.

Abstract: A method, a filtering control device, a computer program and a computer program product for processing a first picture in a sample adaptive filtering procedure are disclosed. The first picture is reconstructed from video data. The filtering control device obtains an offset magnitude from the video data. The offset magnitude indicates a magnitude of a sample adaptive offset to be applied in the sample adaptive filtering procedure. The filtering control device obtains an offset sign from the video data. The offset sign indicates a sign of the sample adaptive offset. The filtering control device determines the sample adaptive offset based on the offset magnitude and the offset sign. Moreover, the filtering control device processes, in the sample adaptive filtering procedure, at least a portion of the first picture while applying the sample adaptive offset.

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: 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: 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: An example method includes receiving a video bitstream with a high fidelity input format and side information related to the video bitstream. The side information includes a video bitstream representing the original video source with a low fidelity input 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. The method further includes decoding the side information to generate transcoding guiding information, estimating a representation of video bitstream with a low fidelity output format, based on the received bit stream and the generated transcoding guiding information, improving the estimated low-fidelity representation by adding the transform coefficients of the side information to transform coefficients generated from the estimated low-fidelity representation, and encoding the improved estimated representation of the low-fidelity bitstream.