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Hallapuro, Tampere

Antti Hallapuro, Tampere FI

Patent application numberDescriptionPublished
20090052535SYSTEM AND METHOD FOR PROVIDING IMPROVED INTRA-PREDICTION IN VIDEO CODING - A system and method for improving the efficiency of decoding intra-coded blocks in video decoding, even in the event that neighboring pixels of the block are unavailable. According to various embodiments, in addition to information that is used to describe how a prediction is formed using a specified process, other “side” information is also transmitted for use in the decoding process. For example, after the intra-prediction direction of a block is decoded, it is determined whether the intra-prediction requires pixels that are unavailable for the block. If such pixels are needed, than side information may be parsed from the bitstream in a predetermined manner. The prediction signal may then be reconstructed for the block using various pieces of information.02-26-2009
20100195923IMPLEMENTATION OF A TRANSFORM AND OF A SUBSEQUENT QUANTIZATION - An approximation of a DCT and a quantization are to be applied subsequently to digital data for compression of this digital data. In order to improve the transform, a predetermined transform matrix is simplified to require less operations when applied to digital data. In addition, elements of the simplified transform matrix constituting irrational numbers are approximated by rational numbers. These measures are compensated by extending a predetermined quantization to include the operations which were removed in the simplification of the predetermined transform matrix. The included operations are further adjusted to compensate for the approximation of elements of the simplified transform matrix by rational numbers. If the simplified transform matrix and the extended quantization are used as basis for implementation, a fast transform with a good resulting quality can be achieved. An approximation of an IDCT employed in decompression of compressed digital data can be simplified correspondingly.08-05-2010

Patent applications by Antti Hallapuro, Tampere FI

Antti Olli Hallapuro, Tampere FI

Patent application numberDescriptionPublished
20090016626JOINT CODING OF MULTIPLE TRANSFORM BLOCKS WITH REDUCED NUMBER OF COEFFICIENTS - A system and method for video/image encoding and decoding, where transform coefficients associated with a plurality of blocks are reorganized and coded together. Various embodiments perform transform and quantization and generate transform coefficients, where the coefficients of the transform blocks are reorganized and interleaved. Additionally, an encoding process involves coding only a subset of the transform coefficients belonging to the transform blocks resulting in one or more transform blocks less than the original number of transform blocks, and putting this into a bitstream. A decoding process involves decoding the one or more resulting transform blocks including the subset of transform coefficients from the bistream, the transform coefficients being put in an array and decoded. The decoder de-interleaves the decoded transform coefficients and any remaining coefficients of the one or more transform blocks are filled in according to a plurality of different methods. After the one or more transform blocks are fully decoded, inverse transform and inverse quantization are performed and residual data is generated.01-15-2009
20090097545Fixed-Point Implementation of an Adaptive Image Filter with High Coding Efficiency - In accordance with an embodiment of the present invention, a method comprising: representing coefficients of an adaptive image filter in binary words wherein the coefficients are restricted and the binary words have a maximum number of bits defined at least in part by a precision index; computing at least one of a convolution sum and multiple partial convolution sums of the adaptive image filter wherein the at least one of a convolution sum and multiple partial convolution sums having a constrained value range and having a binary representation with a fixed maximum number of bits; and generating the output of the adaptive image filter based at least in part on the at least one of a convolution sum and multiple partial convolution sums, is disclosed.04-16-2009
20090097547Fixed-Point Implementation of an Adaptive Image Filter with High Coding Efficiency - In accordance with an embodiment of the present invention, a method comprising: representing coefficients of an adaptive image filter in binary words wherein the coefficients are restricted and the binary words have a maximum number of bits defined at least in part by a precision index; computing at least one of a convolution sum and multiple partial convolution sums of the adaptive image filter wherein the at least one of a convolution sum and multiple partial convolution sums having a constrained value range and having a binary representation with a fixed maximum number of bits; and generating the output of the adaptive image filter based at least in part on the at least one of a convolution sum and multiple partial convolution sums, is disclosed.04-16-2009
20090304084COMBINED MOTION VECTOR AND REFERENCE INDEX PREDICTION FOR VIDEO CODING - A system and method for improving the coding efficiency of motion vector information in video coding. According to various embodiments, a list of motion vector predictor candidates is arranged according to predefined rules. Each motion vector also has a reference index associated with it. One of the motion vector candidates is then selected as a predictor based on predefined rules, or the selection is explicitly signaled in the bitstream. The reference index associated with the selected motion vector is used as a reference index for the current block. The reference index is predicted along with the motion vector. Such embodiments can improve the compression efficiency of modern video codecs.12-10-2009
20100150226SWITCHING BETWEEN DCT COEFFICIENT CODING MODES - A system and method is provided for improving efficiency when entropy coding a block of quantized transform coefficients in video coding. Quantized coefficients are coded in two separate coding modes, namely, a run mode to a level mode coding mode. “Rules” for switching between these two modes are provided, and various embodiments are realized by allowing an entropy coder to adaptively decide when to switch between the two coding modes based on context information, the rules and/or by explicitly signaling the position of switching (e.g., whether or not it should switch coding modes).06-17-2010
20100246692FLEXIBLE INTERPOLATION FILTER STRUCTURES FOR VIDEO CODING - Systems and methods of signaling different filter structures for each pixel or sub-pixel position in motion compensation prediction video coding are provided. An encoder signals to a decoder one filter structure among a plurality of pre-defined candidates that is used for a respective pixel or sub-pixel position. In accordance with one embodiment, filter structures signaled to the decoder from the encoder “switch” between directional filter and radial filter structures during interpolation at the sub-pixel level. In accordance with another embodiment, filter structures that are signaled may switch between a directional filter structure and a separable filter structure at the sub-pixel level. Thus, not only can an encoder switch between different filter structures during interpolation, but a filter structure pair is provided that the encoder can utilize to interpolate a wide range of signals without increasing tap-length.09-30-2010
20100295712METHOD FOR CODING AND AN APPARATUS - The disclosure relates to variable length encoding and decoding. A symbol is variable length encoded by selecting a variable length code word table from a set of variable length code word tables based on a value of a variable; selecting a code word from the selected variable length code word table on the basis of said symbol; and updating the value of said variable by comparing the correspondence between said symbol and said variable. If the comparison indicates that the value of the variable is smaller than the symbol, the value of said variable is incremented; else if the comparison indicates that the value of the variable is greater than the symbol, the value of said variable is decremented; else the value of the variable is not amended.11-25-2010

Patent applications by Antti Olli Hallapuro, Tampere FI