Abstract: There is provided a method for processing a bitstream. The method comprises determining a value, N, wherein N identifies a number of ordered layer representations, wherein N is greater than or equal to 3 such that the N ordered layer representations comprises a highest layer representation, a second highest layer representation, and a third highest layer representation. The method further comprises determining a value for the highest layer representation. The method comprises, after determining the value for the highest layer representation and before determining a value for the third highest layer representation, determining a value for the second highest layer representation. The method comprises, after determining the value for the second highest layer representation, determining a value for the third highest layer representation.

Abstract: A method for deriving a value for a first syntax element, Syntax_A. The method comprises determining whether Syntax_A is present in a bitstream. The method comprises, as a result of determining that Syntax_A is not present in the bitstream, deriving the value for Syntax_A to be equal to a first value, B, if a first condition is satisfied, or deriving the value for Syntax_A to be equal to a second value, C, if a second condition is satisfied.

Abstract: In one aspect there is disclosed a method of applying deblocking on implicit vertical TU boundaries when the CU width is larger than the maximum TU width and applying deblocking on implicit horizontal TU boundaries when the CU height is larger than the maximum TU height. Some exemplary embodiments include HEVC deblocking and deblocking using longer filters.

Abstract: A conversion between two texture compression formats comprises calculations performed at index-level for reducing handling of values with color bit-length and an amount of calculations with color values. Format conversion can thus be performed in real time upon displaying an image using the compressed texture data, without significant slowing down of a display rate of the images. It may be implemented in particular for conversion from DXT1—to ETC1 compression format, and a non-flipped or flipped orientation of an ETC1—compressed texture data block can thus be determined from said texture data block as initially compressed in DXT1 format.

Abstract: A portable electronic apparatus has a display, keypad, sensor and controller. Keys of the keypad are distributed within a keypad area in at least a first plane and are arranged for user actuation transversally to the first plane to provide a first type of user input. The sensor is positioned to sense navigating user actuation at the keypad area in or coincident with the first plane to provide a second type of user input. The controller is configured to control a focus position on the display in response to the second type of user input; associate a plurality of display subareas of the display with respective keys of the keypad; and accept, for user input of the second type, user actuation of an actuated key among the keys as a selection of a selectable item presented at the focus position in a particular display subarea associated with the actuated key.

Abstract: A portable electronic apparatus has a display, keypad, sensor and controller. Keys of the keypad are distributed within a keypad area in at least a first plane and are arranged for user actuation transversally to the first plane to provide a first type of user input. The sensor is positioned to sense navigating user actuation at the keypad area in or coincident with the first plane to provide a second type of user input. The controller is configured to control a focus position on the display in response to the second type of user input; associate a plurality of display subareas of the display with respective keys of the keypad; and accept, for user input of the second type, user actuation of an actuated key among the keys as a selection of a selectable item presented at the focus position in a particular display subarea associated with the actuated key.

Abstract: A tile of pixels is encoded by variable length encoding at least a first block of pixels into a first sequence of symbols and a second block of pixels into a second sequence of symbols. The symbols of the first and second sequences are co-organized into a combined sequence of symbols in which the symbols of the first sequence are readable in a first reading direction and at least a portion of the symbols in the second sequence are readable in a second, opposite reading direction. The encoding of the tile to form one or more combined sequences significantly reduces the bandwidth requirements when writing the tile to a pixel value buffer. The co-organization of the first and second sequences enables parallel reading and decoding of the first and second sequences from the pixel value buffer, thereby reducing any decoding latency.

Abstract: A conversion between two texture compression formats comprises calculations performed at index-level for reducing handling of values with color bit-length and an amount of calculations with color values. Format conversion can thus be performed in real time upon displaying an image using the compressed texture data, without significant slowing down of a display rate of the images. It may be implemented in particular for conversion from DXT1—to ETC1 compression format, and a non-flipped or flipped orientation of an ETC1—compressed texture data block can thus be determined from said texture data block as initially compressed in DXT1 format.

Abstract: A tile of pixels is encoded by variable length encoding blocks of pixels constituting different subsets of the tile to form sequences of symbols as encoded representations of the pixel values. A respective size indication is determined for each set of at least block. A size indication is representative of a compression ratio of a combined sequence corresponding to the at least one sequence of symbols obtained for the at least one block of the set. The combined sequences are arranged in in a pixel value buffer in a buffer memory. The size indication determined for a given set is also stored in the pixel value buffer in the buffer memory to precede, according to a reading order of the pixel value buffer, the combined sequence of the given set.

Abstract: Compression of a pixel block having multiple pixels comprises calculating a respective prediction error for each pixel component of the pixels except a defined starting pixel. Respective minimum number of symbols required for representing the prediction errors are determined and used to select a symbol configuration among multiple different symbol configurations. Each such symbol configuration defines respective numbers of symbols maximally available for the different prediction errors. A compressed representation of the pixel block comprises a configuration identifier of the selected symbol configuration, a representation of the pixel value of the defined starting pixel and representations of the prediction errors calculated for the remaining pixels.

Abstract: A decoding system comprises N different decoders each having a unique circuitry that is different from the circuitries of the other N?1 decoders. The decoders each generate at least one texel value based on an input encoded texel block. A value selector is configured to selectively output at least N texel values from at least one of the decoders based on the position of the at least N texels relative a boundary of a texel block comprising at least one of the at least N texels. A pixel calculator calculates a pixel value of a decoded pixel based on the at least N selected texel values from the value selector.

Abstract: A compressed pixel block (400) is decompressed by defining multiple available property values. At least one reference point relative the pixel block (300) is identified based on a reference codeword (410) of the compressed pixel block (400). Pixel indices of the pixels (310) are determined based on the respective positions of pixels (310) in the pixel block (300) relative the at least one reference point. These pixel indices are used for selecting among the multiple defined property values. The selected property values are then assigned to pixels (310) to be decompressed based on their determined pixel indices.

Abstract: A tile of pixels is encoded by variable length encoding at least a first block of pixels into a first sequence of symbols and a second block of pixels into a second sequence of symbols. The symbols of the first and second sequences are co-organized into a combined sequence of symbols in which the symbols of the first sequence are readable in a first reading direction and at least a portion of the symbols in the second sequence are readable in a second, opposite reading direction. The encoding of the tile to form one or more combined sequences significantly reduces the bandwidth requirements when writing the tile to a pixel value buffer. The co-organization of the first and second sequences enables parallel reading and decoding of the first and second sequences from the pixel value buffer, thereby reducing any decoding latency.

Abstract: First and second codewords are determined, based on first feature vector components of the image elements in an image block, as representations of a first and second component value. Third and fourth codewords are determined, based on second vector components, as representations of a third and fourth component value. First N1 and second N2 resolution numbers are selected based on the relation of a distribution of the first vector components and a distribution of the second vector components. N1 additional component values are generated based on the first and second component values and N2 additional component values are generated based on the third and fourth component values. Component indices indicative of the generated component values are then provided for the different image elements.

Abstract: The invention relates to compression of a pixel block (300) of depth values. A reference codeword (410) is determined as a representation of a reference depth value. A row (420) and a column (430) slope codeword are determined as representations of a basic depth slope for the rows (310) and columns (320) in the block (300), respectively. Representations indicating pixel positions where a slope change occurs along at least a portion of a row (310) or column (320) is determined for at least a subset of the rows (310) or columns (320). A mode codeword (440) is determined as a representation of a set of multiple slope correction patterns. A respect pattern codeword (450) is then selected for rows (310) or columns (320) as identifier of one of the slope correction patterns.

Abstract: A portable electronic apparatus has a display, keypad, sensor and controller. Keys of the keypad are distributed within a keypad area in at least a first plane and are arranged for user actuation transversally to the first plane to provide a first type of user input. The sensor is positioned to sense navigating user actuation at the keypad area in or coincident with the first plane to provide a second type of user input. The controller is configured to control a focus position on the display in response to the second type of user input; associate a plurality of display subareas of the display with respective keys of the keypad; and accept, for user input of the second type, user actuation of an actuated key among the keys as a selection of a selectable item presented at the focus position in a particular display subarea associated with the actuated key.

Abstract: A pixel block (300) is losslessly compressed into a candidate compressed block. If the bit length of the candidate block exceeds a threshold value, the property values of the pixels (310-317) in the block (300) are quantized and the quantized values are losslessly compressed into a new candidate compressed block. The procedure is repeated until a candidate compressed block having good image quality and a bit length below the threshold value is found. A compressed representation (400) of the block (300) is determined based on the found candidate compressed block (420) and an identifier (410) of the used quantization parameter.

Abstract: A pixel block is compressed by providing a respective color component prediction for each pixel in the block. A difference between color components of two neighboring pixels is calculated and compared to a threshold. If the difference is smaller than the threshold, the prediction is calculated based on a first linear combination of the color components of these two neighboring pixels. However, if the difference exceeds the threshold, a second or third linear combination of the color components of the neighboring pixels is employed in the prediction. A guiding bit associated with the selected linear combination may be used. A prediction error is calculated based on the color component of the pixel and the provided prediction. The compressed block comprises an encoded representation of the prediction error and any guiding bit.

Abstract: A pixel block (300) is compressed by selecting a start depth value and a restart depth value based on the multiple depth values of the pixels (310-318) in the block (300). A respective plane representation (430) indicative of which plane of a start or restart depth value plane is determined for the pixels (311-318). These representations (430) are employed for selecting a pixel set comprising at least one other pixel (312, 314-317) in the block (300) for a pixel (318) to be encoded. The depth value(s) of the pixel(s) (312, 314-317) in the set are used for determining a prediction of the depth value of the pixel (318). The depth value and the prediction are employed for calculating a prediction error, which is encoded. The compressed pixel block (400) comprises the encoded prediction errors (460), a start value representation (420), a restart value representation (430) and the plane representations (440).

Abstract: A decoding system comprises N different decoders each having a unique circuitry that is different from the circuitries of the other N?1 decoders. The decoders each generate at least one texel value based on an input encoded texel block. A value selector is configured to selectively output at least N texel values from at least one of the decoders based on the position of the at least N texels relative a boundary of a texel block comprising at least one of the at least N texels. A pixel calculator calculates a pixel value of a decoded pixel based on the at least N selected texel values from the value selector.