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Sanjeev Mehrotra, Wei Ge Chen, Kazuhito Koishida: Modification of codewords in dictionary used for efficient coding of digital media spectral data. Microsoft Corporation, Klarquist Sparkman, July 14, 2009: US07562021 (27 worldwide citation)

Coding of spectral data by representing certain portions of the spectral data as a scaled version of a code-vector, where the code-vector is chosen from either a fixed predetermined codebook or a codebook taken from a baseband. Various optional features are described for modifying the code-vectors i ...


32
Sanjeev Mehrotra, Wei Ge Chen: Low complexity decoder for complex transform coding of multi-channel sound. Microsoft Corporation, Klarquist Sparkman, October 25, 2011: US08046214 (26 worldwide citation)

A multi-channel audio decoder provides a reduced complexity processing to reconstruct multi-channel audio from an encoded bitstream in which the multi-channel audio is represented as a coded subset of the channels along with a complex channel correlation matrix parameterization. The decoder translat ...


33
Naveen Thumpudi, Wei Ge Chen, Chao He: Coding and decoding scale factor information. Microsoft Corporation, Klarquist Sparkman, May 26, 2009: US07539612 (26 worldwide citation)

Techniques and tools for representing, coding, and decoding scale factor information are described herein. For example, during encoding of scale factors, an encoder uses one or more of flexible scale factor resolution selection, spatial prediction of scale factors, flexible prediction of scale facto ...


34
Sanjeev Mehrotra, Wei Ge Chen: Selectively using multiple entropy models in adaptive coding and decoding. Microsoft Corporation, Klarquist Sparkman, October 6, 2009: US07599840 (25 worldwide citation)

Techniques and tools for selectively using multiple entropy models in adaptive coding and decoding are described herein. For example, for multiple symbols, an audio encoder selects an entropy model from a first model set that includes multiple entropy models. Each of the multiple entropy models incl ...


35
Wei Ge Chen, Chao He: Mixed lossless audio compression. Microsoft Corporation, Klarquist Sparkman, May 19, 2009: US07536305 (24 worldwide citation)

A mixed lossless audio compression has application to a unified lossy and lossless audio compression scheme that combines lossy and lossless audio compression within a same audio signal. The mixed lossless compression codes a transition frame between lossy and lossless coding frames to produce seaml ...


36
Wei Ge Chen, Chao He: Innovations in pure lossless audio compression. Microsoft Corporation, Klarquist Sparkman, February 5, 2008: US07328150 (23 worldwide citation)

A lossless audio compression scheme is adapted for use in a unified lossy and lossless audio compression scheme. In the lossless compression, the adaptation rate of an adaptive filter is varied based on transient detection, such as increasing the adaptation rate where a transient is detected. A mult ...


37
Sanjeev Mehrotra, Wei Ge Chen: Adaptive vector Huffman coding and decoding based on a sum of values of audio data symbols. Microsoft Corporation, Klarquist Sparkman, October 26, 2010: US07822601 (22 worldwide citation)

An audio encoder performs entropy encoding of audio data. For example, an audio encoder determines a Huffman code from a Huffman code table to use for encoding a vector of audio data symbols, where the determining is based on a sum of values of the audio data symbols. An audio decoder performs corre ...


38
Wei Ge Chen, Naveen Thumpudi, Ming Chieh Lee: Accounting for non-monotonicity of quality as a function of quantization in quality and rate control for digital audio. Microsoft Corporation, Klarquist Sparkman, August 28, 2007: US07263482 (22 worldwide citation)

An audio encoder regulates quality and bitrate with a control strategy. The strategy includes several features. For example, an encoder selects a quantization level within a range of quantization levels, where the selecting accounts for non-monotonicity of quality measure as a function of quantizati ...


39
Wei Ge Chen, Ming Chieh Lee, Naveen Thumpudi: Filtering of control parameters in quality and rate control for digital audio. Microsoft Corporation, Klarquist Sparkman, August 21, 2007: US07260525 (22 worldwide citation)

An audio encoder regulates quality and bitrate with a control strategy. The strategy includes several features. First, an encoder regulates quantization using quality, minimum bit count, and maximum bit count parameters. Second, an encoder regulates quantization using a noise measure that indicates ...


40
Sanjeev Mehrotra, Wei Ge Chen: Efficient coding of digital media spectral data using wide-sense perceptual similarity. Microsoft Corporation, Klarquist Sparkman, December 2, 2008: US07460990 (22 worldwide citation)

Traditional audio encoders may conserve coding bit-rate by encoding fewer than all spectral coefficients, which can produce a blurry low-pass sound in the reconstruction. An audio encoder using wide-sense perceptual similarity improves the quality by encoding a perceptually similar version of the om ...