Abstract: An example apparatus includes a memory configured to store the audio data; and one or more processors in communication with the memory, the one or more processors configured to: decode, from an encoded audio bitstream, a unique identifier for each of a plurality of subbands of audio data; perform inverse pyramid vector quantization (PVQ) using a compact map to reconstruct a residual vector for each subband of the plurality of subbands of the audio data based on the unique identifier for the respective subband of the plurality of subbands of the audio data, wherein the compact map is generated using structural unification of vectors across subbands and relational compression, and wherein the unique identifiers correspond to codevectors; and reconstruct, based on the residual vectors and energy scalars for each subband, the plurality of subbands of the audio data.

Abstract: A method of encoding audio data includes determining an energy level of a first subband of frequency domain audio data, determining a bit allocation for a coarse quantization process and a fine quantization process, determining that the energy level of the first subband of frequency domain audio data is outside a predetermined range of energy levels for the coarse quantization process, reallocating bits assigned to the fine quantization process to an extended-range coarse quantization process, the extended-range coarse quantization process using an extended range of energy levels, wherein the extended range of energy levels is larger than the predetermined range of energy levels for the coarse quantization process, and quantizing the energy level of the first subband of frequency domain audio data using the extended-range coarse quantization process to produce a quantized extended-range coarse energy level.

Abstract: Adaptations for in-vehicle adaptive noise-canceling (ANC) technology are described. An example in-vehicle audio system includes ANC circuitry coupled to one or more error microphones. The ANC circuitry being configured to process audio data received from the one or more error microphones to determine a distinction between the engine-external noise and the engine noise. The ANC circuitry is further configured to alter, based on the distinction determined between the engine-external noise and the engine noise, a convergence between two or more ANC filters to form altered-convergence ANC filtering coefficients.

Abstract: Embodiments are directed towards providing speech enhancement of audio signals from a target source and noise reduction of audio signals from a noise source. A coherence between a first audio signal from a first microphone and a second audio signal from a second microphone may be determined. A first gain function may be determined based on real components of a coherence function, wherein the real components include coefficients based on the previously determined coherence. A second gain function may be determined based on imaginary components of the coherence function. And a third gain function may be determined based on a relationship between a real component of the coherence function and a threshold range. An enhanced audio signal may be generated by applying a combination of the first gain function, the second gain function, and the third gain function to the first audio signal.

Abstract: Embodiments are directed towards providing speech enhancement of audio signals from a target source and noise reduction of audio signals from a noise source. A coherence between a first audio signal from a first microphone and a second audio signal from a second microphone may be determined. A first gain function may be determined based on real components of a coherence function, wherein the real components include coefficients based on the previously determined coherence. A second gain function may be determined based on imaginary components of the coherence function. And a third gain function may be determined based on a relationship between a real component of the coherence function and a threshold range. An enhanced audio signal may be generated by applying a combination of the first gain function, the second gain function, and the third gain function to the first audio signal.

Abstract: Embodiments are directed towards enhancing speech and noise reduction for audio signals. Each of a plurality of microphones may generate a plurality of audio signals based on sound sensed in a physical space. One of the plurality of audio signals may be designated as a primary channel and each other audio signal of the plurality of audio signals may be designated as secondary channels. Acoustic echo cancellation is performed on the primary channel to generate an echo canceled signal. Noise reduction (e.g., employing a multi-microphone beamformer) is performed on the primary channel and the secondary channels to generate a noise reduced signal. In various embodiments, the noise reduction is performed in parallel with the acoustic echo cancellation. An enhanced audio signal may be generated based on a combination of the echo canceled signal and the noise reduced signal.

Abstract: Embodiments are directed towards providing acoustic echo cancellation in a closely-coupled microphone/speaker system. A speaker may produce an audible signal from a reference signal, which may be captured with a microphone. Full band cancellation (FBC) may modify the captured signal to suppress an echo of the reference signal caused by a direct acoustic path between the microphone and speaker. FBC may include a fixed filter and an adaptive filter. The fixed filter may modify the captured signal based on the reference signal. The adaptive filter may automatically adapt based on the captured signal and the reference signal. If a comparison of a performance of the adaptive filter and the fixed filter is above a threshold, then the fixed filter may be updated based on the adaptive filter. Subband acoustic echo cancellation may generate an output signal that suppresses residual echoes of the reference signal based on the modified signal.

Abstract: Embodiments are directed towards a speaker/microphone system. Each microphone in a microphone array generate an audio signal based on sound in a physical space. The microphone array may be arranged to logically define the physical space into a plurality of regions that have a status of active or inactive. An output signal may be generated from the audio signals, such that directional noise reduction is performed on audio signals associated with inactive regions and speech enhancement is performed on audio signals associated with active regions. A region's current status may be modified to its opposite status based on a request provided by a user. The request may be triggered by an activator or a spoken word/phrase provided by the user. An indication may be provided to the user regarding each current status for each region. The indication may also represent a quality of audio signals associated with active regions.

Abstract: Embodiments are directed towards providing acoustic echo cancellation in a closely-coupled microphone/speaker system. A speaker may produce an audible signal from a reference signal, which may be captured with a microphone. Full band cancellation (FBC) may modify the captured signal to suppress an echo of the reference signal caused by a direct acoustic path between the microphone and speaker. FBC may include a fixed filter and an adaptive filter. The fixed filter may modify the captured signal based on the reference signal. The adaptive filter may automatically adapt based on the captured signal and the reference signal. If a comparison of a performance of the adaptive filter and the fixed filter is above a threshold, then the fixed filter may be updated based on the adaptive filter. Subband acoustic echo cancellation may generate an output signal that suppresses residual echoes of the reference signal based on the modified signal.

Abstract: Embodiments are directed towards enabling headphones to perform active noise cancellation for a particular user. Each separate user may enable individualized noise canceling headphones for one or more noise environments. When the user is wearing the headphones in a quiet environment, a user may employ a computer to initiate determination of a plant model of each ear cup specific to the user. When the user is wearing the headphones in a target noise environment, the user may utilize the computer to initiate determination of operating parameters of a controller for each ear cup of the headphones. The computer may provide the operating parameters of each controller to the headphones. And the operation of each controller may be updated based on the determined operating parameters. The updated headphones may be utilized by the user to provide active noise cancellation.

Abstract: A signal processor for estimating noise power in an audio signal includes a filter unit for generating a series of power values, each power value representing the power in the audio signal at a respective one of a plurality of frequency bands; a signal classification unit for analysing successive portions of the audio signal to assess whether each portion contains features characteristic of speech, and for classifying each portion in dependence on that analysis; a correction unit for estimating a minimum power value in a time-limited part of the audio signal, estimating the total noise power in that part of the audio signal and forming a correction factor dependent on the ratio of the minimum power value to the estimated total noise power, the correction unit being configured to estimate the minimum power value and the total noise power over only those portions of the time-limited part of the signal that are classified by the signal classification unit as being less characteristic of speech; and a noise estim

Abstract: Embodiments are directed towards providing acoustic echo cancellation in a closely-coupled microphone/speaker system. A speaker may produce an audible signal from a reference signal, which may be captured with a microphone. Full band cancellation (FBC) may modify the captured signal to suppress an echo of the reference signal caused by a direct acoustic path between the microphone and speaker. FBC may include a fixed filter and an adaptive filter. The fixed filter may modify the captured signal based on the reference signal. The adaptive filter may automatically adapt based on the captured signal and the reference signal. If a comparison of a performance of the adaptive filter and the fixed filter is above a threshold, then the fixed filter may be updated based on the adaptive filter. Subband acoustic echo cancellation may generate an output signal that suppresses residual echoes of the reference signal based on the modified signal.

Abstract: Embodiments are directed towards providing acoustic echo cancellation in a closely-coupled microphone/speaker system. A speaker may produce an audible signal from a reference signal, which may be captured with a microphone. Full band cancellation (FBC) may modify the captured signal to suppress an echo of the reference signal caused by a direct acoustic path between the microphone and speaker. FBC may include a fixed filter and an adaptive filter. The fixed filter may modify the captured signal based on the reference signal. The adaptive filter may automatically adapt based on the captured signal and the reference signal. If a comparison of a performance of the adaptive filter and the fixed filter is above a threshold, then the fixed filter may be updated based on the adaptive filter. Subband acoustic echo cancellation may generate an output signal that suppresses residual echoes of the reference signal based on the modified signal.

Abstract: A method, apparatus, and manufacture of beamforming is provided. Adaptive null beamforming is performed for signals from first and second microphones of a two-microphone array. The signals from the microphones are decomposed into subbands. Beamforming weights are evaluated and adaptively updated over time based, at least in part, on the direction of arrival and distance of the target signal. The beamforming weights are applied to the subbands at each updated time interval. Each subband is then combined.

Abstract: A portable music player for the playback of a digital audio file comprises a memory for storing a plurality of digital audio files; an audio output; a control for setting a desired change in pitch or tempo; and a digital signal processor configured to process a digital audio file and recover an audio signal therefrom, perceptibly alter one of the pitch and the tempo of the audio signal in response to the desired change in pitch or tempo without perceptibly altering the other of the pitch and tempo, and output the altered audio signal to the audio output.

Abstract: An active noise cancellation controller for performing noise attenuation in a system over a predetermined frequency rang. The controller comprises several components: a first input for a reference signal indicative of a noise level; a second input for receiving an error signal indicative of a remnant noise level; an output for providing a noise cancellation signal; a fixed feedback controller for processing the error signal; a fixed feed-forward controller for processing the reference signal; and an adaptive feed-forward controller having a digital adaptive finite impulse response filter arranged for operation on the reference signal the error signal.

Abstract: An active noise cancellation controller for performing noise attenuation in a system over a predetermined frequency rang. The controller comprises several components: a first input for a reference signal indicative of a noise level; a second input for receiving an error signal indicative of a remnant noise level; an output for providing a noise cancellation signal; a fixed feedback controller for processing the error signal; a fixed feed-forward controller for processing the reference signal; and an adaptive feed-forward controller having a digital adaptive finite impulse response filter arranged for operation on the reference signal the error signal.

Abstract: An audio processing device for reducing the effect on a first signal of echo from a second signal, the device comprising: an echo reduction processor for processing the first signal to reduce echo in it, the echo reduction unit having: a first mode of operation for reducing echo of a first function from the first signal; and a second mode of operation for reducing echo of a second function from the first signal, the second function being more complex than the first function and the echo reduction processor being such as to consume more power in the second mode of operation than in the first mode of operation; and an echo reduction controller for controlling the echo reduction processor to operate in a selected one of the first mode of operation and the second mode of operation.

Abstract: Embodiments are directed towards enabling headphones to perform active noise cancellation for a particular user. Each separate user may enable individualized noise canceling headphones for one or more noise environments. When the user is wearing the headphones in a quiet environment, a user may employ a computer to initiate determination of a plant model of each ear cup specific to the user. When the user is wearing the headphones in a target noise environment, the user may utilize the computer to initiate determination of operating parameters of a controller for each ear cup of the headphones. The computer may provide the operating parameters of each controller to the headphones. And the operation of each controller may be updated based on the determined operating parameters. The updated headphones may be utilized by the user to provide active noise cancellation.

Abstract: A method for obtaining coefficients for a non-adaptive controller for use in an active noise control system, the method comprising capturing experimental data from a target system to characterise the plant of the target system; and implementing an adaptive algorithm to compute the coefficients in dependence on the experimental data.