Abstract: Image data encoding apparatus, comprises an entropy encoder configured to selectively encode data items representing image data so as to generate encoded binarized symbols of successive output data units; the entropy encoder being configured to generate an output data stream subject to a constraint defining an upper limit to the number of binarized symbols that may be expressed by any individual output data unit relative to the size in bytes of that output data unit, in which the entropy encoder is configured to provide padding data, for each output data unit which does not meet the constraint, so as to increase the size in bytes of that output data unit in order to meet the constraint; the apparatus comprising: an attribute detector configured to detect an encoding attribute applicable to a given output data unit; and a selector configured to select, in response to the detected encoding attribute, a constraint, for use with the given output data unit, from two or more candidate constraints.

Abstract: Image data encoding apparatus comprises an entropy encoder for selectively encoding data items representing image data to be encoded by a first, context adaptive binary arithmetic coding (CABAC), encoding system or by a second, bypass, encoding system, so as to generate encoded binarized symbols; the image data representing one or more pictures of a picture sequence, each picture comprising two or more output data units representing respective sub-sections of the picture, each sub-section being decodable and reconstructable independently of other sub-sections in that picture and picture sequence; in which each sub-section is subject to a respective minimum compression ratio.

Abstract: A method of encoding successive data items comprises storing history data for encoded data items, the history data indicating one or more aspects of encoding the encoded data items; encoding a given data item by a first encoding technique comprising encoding a series of zero or more data sets, each data set representing a respective range of values of the data items and selecting the series of data sets from a plurality of candidate data sets in dependence upon (i) a number of previously encoded data sets; and (ii) the history data applicable to a given property of the given data item; and encoding any remaining value of the given data item, the remaining value being an amount by which the given data item exceeds a maximum value which can be encoded by the first encoding technique, by a second encoding technique different to the first encoding technique.

Abstract: An apparatus including a video data decoder configured to decode an input video data stream, the video data decoder being responsive to a parameter value associated with the input video data stream, the parameter value indicating an encoding level selected from a plurality of encoding levels, each encoding level defining at least a maximum luminance picture size and a maximum luminance sample rate, the encoding level defining a first numerical component and a second numerical component, the second numerical component being a numerical value greater than or equal to zero, in which for encoding levels having a second numerical component of zero, the first numerical component increases monotonically with increasing maximum luminance picture size, and the second component varies with the maximum luminance sample rate; the parameter value being a numeric encoding of the encoding level.

Abstract: A data encoding method comprises generating one or more encoding parameters; communicating the one or more encoding parameters for use by a decoding process; and encoding data items representing image data samples of an image by generating residual data indicative of a difference between an image data sample and a predicted version of that image data sample, the encoding step performing the encoding in dependence upon the one or more encoding parameters generated by the generating step; in which the generating step comprises deriving an estimate of the residual data in respect of at least a subset of the image data samples and generating the one or more encoding parameters in dependence upon the derived estimate.

Abstract: A method of encoding successive data items comprises storing history data for encoded data items, the history data indicating one or more aspects of encoding the encoded data items; encoding a given data item by a first encoding technique comprising encoding a series of zero or more data sets, each data set representing a respective range of values of the data items and selecting the series of data sets from a plurality of candidate data sets in dependence upon (i) a number of previously encoded data sets; and (ii) the history data applicable to a given property of the given data item; and encoding any remaining value of the given data item, the remaining value being an amount by which the given data item exceeds a maximum value which can be encoded by the first encoding technique, by a second encoding technique different to the first encoding technique.

Abstract: A video data encoding method for encoding an array of video data values comprises the steps of: frequency-transforming the video data values according to a frequency transform, to generate an array of frequency-transformed values by a matrix-multiplication process using a transform matrix having a data precision of fourteen bits, the frequency transform being a discrete cosine transform; defining a 64×64 transform matrix M64 for a 64×64 DCT transform, the matrix M64 being defined by the accompanying FIGS. 10a-10e and 11; for an N×N transform where N is 2, 4, 8 or 16, subsampling the 64×64 transform matrix M64 to select a subset of N×N values, the subset MN[x][y] of values being defined by: MN[x][y]=M64[x][(2(6-log2(N)))y] for x,y=0 . . . (N?1).

Abstract: Apparatus comprises a data encoder configured to derive, from an array of sample values, sample range flags each indicative of whether one or more sample values of the array of sample values lie in a predetermined range of sample values, the data encoder being configured in a first encoding mode to encode the array of sample values, at least in part, by encoding the sample range flags to an output data stream; a predictor configured to predict the state of a group of the sample range flags for a given array of sample values, the group being at least a subset of the sample range flags; and a comparator configured to compare the predicted state of the group of sample range flags with the actual state of the respective sample range flags for the given array of sample values; the data encoder being configured, in response to the comparator, to encode the given array of samples values in a second encoding mode in which the encoder is configured to encode to the output data stream a predetermined number of indicato

Abstract: Apparatus comprises video data decoder circuitry configured to decode an input video data stream, the video data decoder being responsive to parameter data associated with the input video data stream, the parameter data indicating a profile selected from a plurality of profiles, each profile defining a decoding attribute comprising one or more of a bit depth and a chrominance subsampling format; detector circuitry configured to detect constraint data associated with the input video data stream, the constraint data defining a difference between a decoding attribute applicable to the input video data stream and the decoding attribute defined by the profile indicated by the parameter data, in which the constraint data is configured to indicate a zero difference of the decoding attribute by a zero value of the constraint data; and control circuitry configured to control the video data decoder to decode the input video data stream to generate a decoded video data stream having a decoding attribute defined by the e

Abstract: Apparatus comprises video data decoder circuitry configured to decode an input video data stream, the video data decoder being responsive to parameter data associated with the input video data stream, the parameter data indicating a profile selected from a plurality of profiles, each profile defining a decoding attribute comprising one or more of a bit depth and a chrominance subsampling format; detector circuitry configured to detect constraint data associated with the input video data stream, the constraint data defining a difference between a decoding attribute applicable to the input video data stream and the decoding attribute defined by the profile indicated by the parameter data, in which the constraint data is configured to indicate a zero difference of the decoding attribute by a zero value of the constraint data; and control circuitry configured to control the video data decoder to decode the input video data stream to generate a decoded video data stream having a decoding attribute defined by the e

Abstract: A method of encoding successive data items comprises storing history data for encoded data items, the history data indicating one or more aspects of encoding the encoded data items; encoding a given data item by a first encoding technique comprising encoding a series of zero or more data sets, each data set representing a respective range of values of the data items and selecting the series of data sets from a plurality of candidate data sets in dependence upon (i) a number of previously encoded data sets; and (ii) the history data applicable to a given property of the given data item; and encoding any remaining value of the given data item, the remaining value being an amount by which the given data item exceeds a maximum value which can be encoded by the first encoding technique, by a second encoding technique different to the first encoding technique.

Abstract: Apparatus comprises a video data decoder; and a coded picture buffer to buffer successive portions of an input video data and provide a portion to the video data decoder for decoding, the coded picture buffer having a coded picture buffer size; the video data decoder being responsive to parameter data associated with the input video data, the parameter data indicating, for a given input video data, an encoding level selected from a plurality of encoding levels, each level defining at least a maximum luminance picture size, a minimum compression ratio and a maximum value of the coded picture buffer size; in which for each encoding level of the plurality of encoding levels, the maximum value of the coded picture buffer size is greater than or equal to the number of bits required to represent a picture at the maximum luminance picture size when encoded according to the minimum compression ratio.

Abstract: A video data encoding method for encoding an array of video data values comprises the steps of: frequency-transforming the video data values according to a frequency transform, to generate an array of frequency-transformed values by a matrix-multiplication process using a transform matrix having a data precision of fourteen bits, the frequency transform being a discrete cosine transform; defining a 64×64 transform matrix M64 for a 64×64 DCT transform, the matrix M64 being defined by the accompanying FIGS. 10a-10e and 11; for an N×N transform where N is 2, 4, 8 or 16, subsampling the 64×64 transform matrix M64 to select a subset of N×N values, the subset MN[x][y] of values being defined by: MN[x][y]=M64[x][(2(6-log2(N)))y] for x,y=0 . . . (N?1).

Abstract: An apparatus including a video data decoder configured to decode an input video data stream, the video data decoder being responsive to a parameter value associated with the input video data stream, the parameter value indicating an encoding level selected from a plurality of encoding levels, each encoding level defining at least a maximum luminance picture size and a maximum luminance sample rate, the encoding level defining a first numerical component and a second numerical component, the second numerical component being a numerical value greater than or equal to zero, in which for encoding levels having a second numerical component of zero, the first numerical component increases monotonically with increasing maximum luminance picture size, and the second component varies with the maximum luminance sample rate; the parameter value being a numeric encoding of the encoding level.

Abstract: A method of encoding video data values, the method including selectively encoding, via circuitry, a high bit depth control flag and, when the high bit depth control flag is set to indicate high bit depth operation, selectively encoding an extended precision flag to indicate at least extended precision operation of a spatial frequency transform stage and encoding the video data values according to a mode of operation defined by the encoded high bit depth control flag and, when encoded, the extended precision flag.

Abstract: Image data encoding apparatus, comprises an entropy encoder configured to selectively encode data items representing image data so as to generate encoded binarized symbols of successive output data units; the entropy encoder being configured to generate an output data stream subject to a constraint defining an upper limit to the number of binarized symbols that may be expressed by any individual output data unit relative to the size in bytes of that output data unit, in which the entropy encoder is configured to provide padding data, for each output data unit which does not meet the constraint, so as to increase the size in bytes of that output data unit in order to meet the constraint; the apparatus comprising: an attribute detector configured to detect an encoding attribute applicable to a given output data unit; and a selector configured to select, in response to the detected encoding attribute, a constraint, for use with the given output data unit, from two or more candidate constraints.

Abstract: Image data encoding apparatus comprises an entropy encoder for selectively encoding data items representing image data to be encoded by a first, context adaptive binary arithmetic coding (CABAC), encoding system or by a second, bypass, encoding system, so as to generate encoded binarized symbols; the image data representing one or more pictures of a picture sequence, each picture comprising two or more output data units representing respective sub-sections of the picture, each sub-section being decodable and reconstructable independently of other sub-sections in that picture and picture sequence; in which each sub-section is subject to a respective minimum compression ratio.

Abstract: Image data encoding and/or decoding apparatus comprises an inter-image predictor configured to predict samples of a current image region, of a plurality of regions of an image in a sequence of images, with respect to a reference image region of another, reference, image of the sequence of images, according to a direction vector indicating a spatial displacement of the reference image region from the current image region;an interpolation filter configured to generate the predicted samples of the current image region by spatial interpolation of samples of the reference image region, at least in instances where the direction vector indicates a spatial displacement of a non-integer number of samples, in which the interpolation filter is configured to operate according to a set of filter parameters each defining the spatial frequency response of a set of filters providing interpolation at a spatial displacement resolution of 1/m sample, where m is an integer greater than one; and a filter response selector configu

Abstract: Apparatus comprises video data decoder circuitry configured to decode an input video data stream, the video data decoder being responsive to parameter data associated with the input video data stream, the parameter data indicating a profile selected from a plurality of profiles, each profile defining a decoding attribute comprising one or more of a bit depth and a chrominance subsampling format; detector circuitry configured to detect constraint data associated with the input video data stream, the constraint data defining a difference between a decoding attribute applicable to the input video data stream and the decoding attribute defined by the profile indicated by the parameter data, in which the constraint data is configured to indicate a zero difference of the decoding attribute by a zero value of the constraint data; and control circuitry configured to control the video data decoder to decode the input video data stream to generate a decoded video data stream having a decoding attribute defined by the e

Abstract: Apparatus comprises a video data decoder configured to decode an input video data stream, the video data decoder being responsive to a parameter value associated with the input video data stream, the parameter value indicating an encoding level selected from a plurality of encoding levels, each encoding level defining at least a maximum luminance picture size and a maximum luminance sample rate; the encoding level defining a first numerical component and a second numerical component, the second numerical component being a numerical value greater than or equal to zero; in which: for encoding levels having a second numerical component of zero, the first numerical component increases monotonically with increasing maximum luminance picture size; second component varies with the maximum luminance sample rate; the parameter value being a numeric encoding of the encoding level a first predetermined constant multiplied by the first numerical component plus a second predetermined constant multiplied by the second nume