Provided are, among other things, systems, apparatuses methods and techniques for generating discrete-time sinusoidal sequences. One such apparatus includes a plurality of parallel processing branches, with each of the parallel processing branches operating at a subsampled rate and utilizing a recursive filter to generate sub-rate samples which represent a different subsampling phase of a complete signal that is output by the apparatus.

The present disclosure discloses an image decompression method, device, and display terminal. The method includes: a step of acquiring image compression data; a step of performing inverse quantization on the image compression data based on a preset inverse quantization factor to obtain inversely quantized data; wherein the inverse quantization factor is in integer form; and a step of performing an inverse discrete cosine transformation (DCT) on the inversely quantized data to obtain image data; wherein the inverse DCT includes bit-shift operations and addition operations.

Multiple transform sizes improve video coding efficiency, but also increase the implementation complexity. Furthermore, both forward and inverse transforms need to be supported in various consumer devices. Embodiments provide a unified forward and inverse transform architecture that supports computation of both forward and inverse transforms for multiple transforms sizes using shared hardware circuits. The unified architecture exploits the symmetry properties of forward and inverse transform matrices to achieve hardware sharing across different the transform sizes and also between forward and inverse transform computations.

A method of encoding a video stream in a video encoder is provided that includes computing an offset into a transform matrix based on a transform block size, wherein a size of the transform matrix is larger than the transform block size, and wherein the transform matrix is one selected from a group consisting of a DCT transform matrix and an IDCT transform matrix, and transforming a residual block to generate a DCT coefficient block, wherein the offset is used to select elements of rows and columns of a DCT submatrix of the transform block size from the transform matrix.

Reconstructing a video signal based on low-complexity DST7 design including obtaining a transform index of a current block from the video signal and deriving a transform combination corresponding to the transform index. The transform index corresponds to any one of a plurality of transform combinations including a combination of DST7 and/or DCT8, and the transform combination includes horizontal and vertical transforms that correspond to at least one of the DST7 or the DCT8. The reconstruction also includes performing an inverse transform in a vertical direction by using the DST7, performing an inverse transform in a horizontal direction by using the DCT8, and reconstructing the video signal by using the current block on which the inverse transform is performed. The DST7 includes Discrete Fourier Transform (DFT) and has a different type of DFT structure based on a size of the current block.

Methods and apparatus for improving data transformation in image processing device are disclosed. An example apparatus includes a memory, a data writer to write received first data into the memory in a first order, and a data reader to read the first data from the memory in a second order, wherein the data writer is to write second data into the memory in the second order.

Incremental update of a neighbor graph via an orthogonal transform based indexing is disclosed. One example is a system including a hash transform module to apply an orthogonal transform to a data object in a data stream, and to associate the data object with a collection of ordered hash positions. An indexing module retrieves an index of ordered key positions, where each key position is indicative of data objects in the data stream that have a hash position at the key position. A neighbor determination module determines a ranked collection of neighbors for the data object in a neighbor graph, where the ranking is based on the index. A graph update module incrementally updates the neighbor graph by including the data object as a neighbor for a selected sub-plurality of data objects in the ranked collection.

A method of decoding or encoding including receiving information regarding a video sequence for encoding or decoding, determining, for the encoding or decoding of the video sequence, whether to use a first transform core matrix that is of a first size type or a second transform core matrix that is of a second size type, and based on the determining, transmitting information that causes the video sequence to be encoded or decoded using the determined first transform core matrix or second transform core matrix.

A video data encoding method for encoding an array of video data values includes 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 greater than six bits.

A method for decoding an encoded video bit stream in a video decoder is provided that includes determining a scan pattern type for a transform block to be decoded, decoding a column position X and a row position Y of a last non-zero coefficient in the transform block from the encoded video bit stream, selecting a column-row inverse transform order when the scan pattern type is a first type, selecting a row-column inverse transform order when the scan pattern type is a second type, and performing one dimensional (1D) inverse discrete cosine transformation (IDCT) computations according to the selected transform order to inversely transform the transform block to generate a residual block.