Frank M Baumgarte

7006636, Feb 28, 2006

May 24, 2002

10/155437

Frank Baumgarte - North Plainfield NJ, US
Christof Faller - Murray Hill NJ, US

Agere Systems Inc. - Allentown PA

H04R 5/00
G06F 17/00
G10L 19/00

381 17, 381 1, 700 94, 704501

An auditory scene is synthesized from a mono audio signal by modifying, for each critical band, an auditory scene parameter (e. g. , an inter-aural level difference (ILD) and/or an inter-aural time difference (ITD)) for each sub-band within the critical band, where the modification is based on an average estimated coherence for the critical band. The coherence-based modification produces auditory scenes having objects whose widths more accurately match the widths of the objects in the original input auditory scene.

7039204, May 2, 2006

Sep 18, 2002

10/246165

Frank Baumgarte - Watchung NJ, US

Agere Systems Inc. - Allentown PA

H04B 1/00

381119, 381103, 381107

During mixing of an N-channel input signal to generate an M-channel output signal, the mixed channel signals are equalized (e. g. , amplified) to maintain the overall energy/loudness level of the output signal substantially equal to the overall energy/loudness level of the input signal. In one embodiment, the N input channel signals are converted to the frequency domain on a frame-by-frame basis, and the overall spectral loudness of the N-channel input signal is estimated. After mixing the spectral components for the N input channel signals (e. g. , using weighted summation), the overall spectral loudness of the resulting M mixed channel signals is also estimated. A frequency-dependent gain factor, which is based on the two loudness estimates, is applied to the spectral components of the M mixed channel signals to generate M equalized mixed channel signals. The M-channel output signal is generated by converting the M equalized mixed channel signals to the time domain.

7292901, Nov 6, 2007

Sep 18, 2002

10/246570

Frank Baumgarte - Watchung NJ, US
Peter Kroon - Green Brook NJ, US

Agere Systems Inc. - Allentown PA

H04R 5/00

700 94, 381 23

Part of the spectrum of two or more input signals is encoded using conventional coding techniques, while encoding the rest of the spectrum using binaural cue coding (BCC). In BCC coding, spectral components of the input signals are downmixed and BCC parameters (e. g. , inter-channel level and/or time differences) are generated. In a stereo implementation, after converting the left and right channels to the frequency domain, pairs of left- and right-channel spectral components are downmixed to mono. The mono components are then converted back to the time domain, along with those left- and right-channel spectral components that were not downmixed, to form hybrid stereo signals, which can then be encoded using conventional coding techniques. For playback, the encoded bitstream is decoded using conventional decoding techniques. BCC synthesis techniques may then apply the BCC parameters to synthesize an auditory scene based on the mono components as well as the unmixed stereo components.

7333930, Feb 19, 2008

Mar 14, 2003

10/389000

Frank Baumgarte - Berkeley Heights NJ, US

Agere Systems Inc. - Allentown PA

G10L 19/00

7042001, 704500

The present invention provides an apparatus, method and tangible medium storing instructions for determining tonality of an input audio signal, for selection of corresponding masked thresholds for use in perceptual audio coding. In the various embodiments, the input audio signal is sampled and transformed using a compressed spectral operation to form a compressed spectral representation, such as a cepstral representation. A peak magnitude and an average magnitude of the compressed spectral representation are determined. Depending upon the ratio of peak-to-average magnitudes, a masked threshold is selected having a corresponding degree of tonality, and is used to determine a plurality of quantization levels and a plurality of bit allocations to perceptually encode the input audio signal with a distortion spectrum beneath a level of just noticeable distortion (JND). The invention also includes other methods and variations for selecting substantially tone-like or substantially noise-like masked thresholds for perceptual encoding of the input audio signal.

7583805, Sep 1, 2009

Apr 1, 2004

10/815591

Frank Baumgarte - Sunnyvale CA, US
Christof Faller - Tägerwilen, CH

Agere Systems Inc. - Allentown PA

H03G 3/00
H04R 5/00
G10L 19/00

381 61, 381 62, 381 63, 381 1, 381 17, 381 18, 381 19, 381 20, 381 23, 381 21, 381 22, 7042001, 704500

A scheme for stereo and multi-channel synthesis of inter-channel correlation (ICC) (normalized cross-correlation) cues for parametric stereo and multi-channel coding. The scheme synthesizes ICC cues such that they approximate those of the original. For that purpose, diffuse audio channels are generated and mixed with the transmitted combined (e. g. , sum) signal(s). The diffuse audio channels are preferably generated using relatively long filters with exponentially decaying Gaussian impulse responses. Such impulse responses generate diffuse sound similar to late reverberation. An alternative implementation for reduced computational complexity is proposed, where inter-channel level difference (ICLD), inter-channel time difference (ICTD), and ICC synthesis are all carried out in the domain of a single short-time Fourier transform (STFT), including the filtering for diffuse sound generation.

7627481, Dec 1, 2009

Apr 19, 2005

11/110331

Shyh-Shiaw Kuo - Cupertino CA, US
Frank Baumgarte - Sunnyvale CA, US

Apple Inc. - Cupertino CA

G10L 19/00

704500

An improved audio coding technique encodes audio having a low frequency transient signal, using a long block, but with a set of adapted masking thresholds. Upon identifying an audio window that contains a low frequency transient signal, masking thresholds for the long block may be calculated as usual. A set of masking thresholds calculated for the 8 short blocks corresponding to the long block are calculated. The masking thresholds for low frequency critical bands are adapted based on the thresholds calculated for the short blocks, and the resulting adapted masking thresholds are used to encode the long block of audio data. The result is encoded audio with rich harmonic content and negligible coder noise resulting from the low frequency transient signal.

7639823, Dec 29, 2009

May 25, 2004

10/853394

Frank Baumgarte - Sunnyvale CA, US

Agere Systems Inc. - Allentown PA

H04B 1/00
H04R 5/00
H03G 3/00

381119, 381 17, 381 18, 381107

According to one embodiment, during mixing of an N-channel input signal to generate an M-channel output signal, in at least one frequency sub-band, magnitude equalization is applied to the mixed channel signals such that an amplitude sum magnitude for the N input channels (e. g. , the magnitude of a sum of estimated amplitudes of the N input channels) is approximately equal to an amplitude sum magnitude for the M output channels (e. g. , the magnitude of a sum of estimated amplitudes of the M output channels). In one implementation, magnitude equalization is applied to one or more sub-bands (e. g. , those below 1 kHz), and power equalization is applied to one or more other sub-bands (e. g. , those above 1 kHz) to reduce coloration effects in the output signal.

7644003, Jan 5, 2010

Sep 8, 2004

10/936464

Frank Baumgarte - Sunnyvale CA, US
Jiashu Chen - Basking Ridge NJ, US
Christof Faller - Tagerwilen, CH

Agere Systems Inc. - Allentown PA

G10L 11/04
G10L 19/00
G10L 21/00
H04R 5/00
H04B 14/04

704501, 704201, 704206, 704230, 381 18, 381 23, 375242

Generic and specific C-to-E binaural cue coding (BCC) schemes are described, including those in which one or more of the input channels are transmitted as unmodified channels that are not downmixed at the BCC encoder and not upmixed at the BCC decoder. The specific BCC schemes described include 5-to-2, 6-to-5, 7-to-5, 6. 1-to-5. 1, 7. 1-to-5. 1, and 6. 2-to-5. 1, where “0. 1” indicates a single low-frequency effects (LFE) channel and “0. 2” indicates two LFE channels.