A method for rendering software resistant to reverse engineering. Replace at least one first constant (mathematical expression, etc.) in a computational expression with a second mixed mathematical and bitwise-Boolean expression, the first constant being simpler than the second expression and the second expression being based on the value or the variables found in the first constant (or expression). Evaluation of the second mixed mathematical and bitwise-Boolean expression produces a value preserving the value of the first constant, either: with the original value of the first constant or the original value of the result of the first expression, in which case the second mixed mathematical and bitwise-Boolean expression is obtained from the first constant by converting the first constant by mathematical identities; or, in an encoded form, as a new value, which can be converted back to the original value of the first constant by applying an information-preserving decoding function, in which case the second mixed mathematical and bitwise-Boolean expression is obtained from the first constant by modifying the first constant by a combination of conversion according to mathematical identities and transformation according to an information preserving encoding function.

System and method of interlocking to protect software-mediated program and device behaviours

One or more continuous mappings are defined at a digital media encoder to convert input digital media data in a first high dynamic range format to a second format with a smaller dynamic range than the first format. The encoder converts the input digital media data to the second format with the smaller dynamic range using the continuous mapping and one or more conversion parameters relating to the continuous mapping. The encoder encodes the converted digital media data in a bitstream along with the conversion parameter(s). The conversion parameter(s) enable a digital media decoder to convert the converted digital media data back to the first high dynamic range format from the second format with the smaller dynamic range. Techniques for converting different input formats with different dynamic ranges are described.

High dynamic range data format conversions for digital media

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 system and method for processing a plurality of channels, for example audio channels, in parallel is provided. For example, a plurality of telephony channels are processed in order to detect and respond to call progress tones. The channels may be processed according to a common transform algorithm. Advantageously, a massively parallel architecture is employed, in which operations on many channels are synchronized, to achieve a high efficiency parallel processing environment. The parallel processor may be situated on a data bus, separate from a main general purpose processor, or integrated with the processor in a common board or integrated device. All, or a portion of a speech processing algorithm may also be performed in a massively parallel manner.

Parallel signal processing system and method

Methods and apparatus are provided for adaptive coupled pre-processing and post-processing filters for video encoding and decoding. The apparatus and method encode input data for a picture into a resultant bitstream, wherein said video encoder comprises a pre-filter and a post-filter coupled to the pre-filter, wherein said pre-filter filters the input data for the picture and the post-filter filters in-loop reconstructed data for the picture (900, 915, 950).

Methods and apparatus for adaptive coupled pre-processing and post-processing filters for video encoding and decoding

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.

Shaw Parker

Papers

Simd lapped transform-based digital media encoding/decoding