In certain embodiments, to eliminate DC leakage into surrounding AC values, scaling stage within a photo overlap transform operator is modified such that the off-diagonal elements of the associated scaling matrix have the values of 0. In certain embodiments, the on-diagonal scaling matrix are given the values (0.5, 2). In some embodiments, the scaling is performed using a combination of reversible modulo arithmetic and lifting steps. In yet other embodiments, amount of DC leakage is estimated at the encoder, and preprocessing occurs to mitigate amount of leakage, with the bitstream signaling that preprocessing has occurred. A decoder may then read the signal and use the information to mitigate DC leakage.

Reducing dc leakage in hd photo transform

A block transform-based digital media codec achieves faster performance by re-mapping components of the digital media data into vectors or parallel units on which many operations of the transforms can be performed on a parallel or single-instruction, multiple data (SIMD) basis. In the case of a one-dimensional lapped biorthogonal transform, the digital media data components are re-mapped into vectors on which butterfly stages of both overlap pre-/post-filter and block transform portions of the lapped transform can be performed on a SIMD basis. In the case of a two-dimensional lapped biorthogonal transform, the digital media data components are re-mapped into vectors on which a Hadamard operator of both overlap pre-/post-filter and block transform can be performed on a SIMD basis.

Simd lapped transform-based digital media encoding/decoding

A method includes decompressing first compressed video data to provide uncompressed video data in a first order. The method includes compressing the uncompressed video data to provide second compressed video data in a second order. The decompressing and compressing are based on first and second compression rates, respectively. The first order may be based on fundamental blocks of a frame of video data and the second order is based on lines of the frame of video data. The compressing may include alternating compression of partial portions of a first line of uncompressed video data with compression of partial portions of at least a second line of uncompressed video data to thereby generate a first line of compressed video data corresponding to the first line of uncompressed video data and at least a second line of compressed video data corresponding to the second line of uncompressed video data.

Dynamic video data compression

An audio encoder/decoder uses a combination of an overlap windowing transform and block transform that have reversible implementations to provide a reversible, integer-integer form of a lapped transform. The reversible lapped transform permits both lossy and lossless transform domain coding of an audio signal having variable subframe sizes.

Factorization of overlapping transforms into two block transforms

In certain embodiments, overlap operators are applied during encoding and/or decoding of digital media, where the overlap operators have reduced DC gain mismatch and/or DC leakage between interior overlap operators and overlap operators at the edge and/or corner. In other embodiments, information indicating a selected tile boundary option for overlap processing can be encoded and/or decoded. The selected tile boundary option indicates one of a hard tile boundary option and a soft tile boundary option for processing with overlap operators. Overlap transform processing can then be applied based at least in part on the selected tile boundary option.

Reduced dc gain mismatch and dc leakage in overlap transform processing

A shared lossless Haar transform and an appended discrete cosine transform type-II are combined to form a discrete cosine type-II transform in a parallel pipelined architecture for providing lossless data transformation.

Hsieh S. Hou

Papers

Haar wavelet transform embedded lossless type II discrete cosine transform