Qualcomm Incorporated

Venkatesh Krishnan

Vivek Rajendran

Venkatraman Atti

Subasingha Shaminda Subasingha

Venkatraman S Atti

Ananthapadmanabhan Arasanipalai Kandhadai

Stephane Pierre Villette

Ethan Robert Duni

Venkatraman Srinivasa Atti

Daniel Jared Sinder

Venkata Subrahmanyam Chandra Sekhar Chebiyyam

Sandip Sarkar

Venkata Subrahmanyam Chebiyyam

Ananthapadmanabhan Aasanipalai Kandhadai

Chandra Mouli Polisetty

Ashish Kumar Tawari

Ananthapadmanbhan A Kandhadai

Ananthapadmanabhan Arasanipatai Kandhadai

Robert Ethan Duni

Kumar Ashish Tawari

A method includes receiving a second audio frame at a decoder. The second audio frame follows a first audio frame in an audio signal and includes a first number of bits allocated to primary coding information associated with the second audio frame, a second number of bits allocated to redundant coding information associated with the first audio frame, and an indicator of a frame type of the first audio frame. In response to a frame erasure condition associated with the first audio frame, the second number of bits is determined based on the indicator and used to decode the first audio frame. In clean channel conditions, the first audio frame is received and decoded based on primary coding bits in the first audio frame, and the first number of bits is determined based on the indicator and used to decode the second audio frame.

Systems and methods of communicating redundant frame information

A method includes generating a high-band residual signal based on a high-band portion of an audio signal. The method also includes generating a harmonically extended signal at least partially based on a low-band portion of the audio signal. The method further includes determining a mixing factor based on the high-band residual signal, the harmonically extended signal, and modulated noise. The modulated noise is at least partially based on the harmonically extended signal and white noise.

Estimation of mixing factors to generate high-band excitation signal

A method includes filtering, at a speech encoder, an audio signal into a first group of sub-bands within a first frequency range and a second group of sub-bands within a second frequency range. The method also includes generating a harmonically extended signal based on the first group of sub-bands. The method further includes generating a third group of sub-bands based, at least in part, on the harmonically extended signal. The third group of sub-bands corresponds to the second group of sub-bands. The method also includes determining a first adjustment parameter for a first sub-band in the third group of sub-bands or a second adjustment parameter for a second sub-band in the third group of sub-bands. The first adjustment parameter is based on a metric of a first sub-band in the second group of sub-bands, and the second adjustment parameter is based on a metric of a second sub-band in the second group of sub-bands.

High-band signal modeling

An apparatus includes a first calculator configured to determine a long-term noise estimate of the audio signal. The apparatus also includes a second calculator configured to determine a formant-sharpening factor based on the determined long-term noise estimate. The apparatus includes a filter configured to filter a codebook vector to generate a filtered codebook vector. The filter is based on the determined formant-sharpening factor, and the codebook vector is based on information from the audio signal. The apparatus further includes an audio coder configured to generate a formant-sharpened low-band excitation signal based on the filtered codebook vector.

Systems, methods, apparatus, and computer-readable media for adaptive formant sharpening in linear prediction coding

A method includes generating a first signal corresponding to a first component of a high-band portion of an audio signal. The first component has a first frequency range. The method includes generating a high-band excitation signal corresponding to a second component of the high-band portion of the audio signal. The second component has a second frequency range differs from the first frequency range. The high-band excitation signal is provided to a filter having filter coefficients generated based on the first signal to generate a synthesized version of the high-band portion of the audio signal.

High-band signal coding using mismatched frequency ranges

A method of performing gain adjustment in an electronic device includes determining a first set of spectral frequency values and determining a second set of spectral frequency values. The first set of spectral frequency values corresponds to a high-band portion of an audio signal received at the electronic device. The second set of spectral frequency values approximates the first set of spectral frequency values in the high band portion of the audio signal. The method includes estimating a spectral distortion corresponding to a difference between the first set of spectral frequency values and the second set of spectral frequency values and adjusting, based on the spectral distortion, a gain value corresponding to at least a portion of the audio signal. The method also includes transmitting an encoded bitstream that includes information corresponding to the adjusted gain value and the second set of spectral frequency values.

Systems and methods of performing gain adjustment

A method for mitigating potential frame instability by an electronic device is described. The method includes obtaining a frame subsequent in time to an erased frame. The method also includes determining whether the frame is potentially unstable. The method further includes applying a substitute weighting value to generate a stable frame parameter if the frame is potentially unstable.

Systems and methods for mitigating potential frame instability

A method includes receiving, at a first device, a bit-stream from a second device. The method also includes generating, at a decoder of the first device, a low-band excitation signal from the bit-stream. The method also includes generating a first baseband signal at a high-band excitation generator of the decoder. Generating the first baseband signal includes performing a spectral flip operation on a nonlinearly transformed version of the low-band excitation signal, and the first baseband signal corresponds to a first sub-band of a high-band portion of an audio signal received at the second device. The method also includes generating a second baseband signal corresponding to a second sub-band of the high-band portion of the audio signal. The method also includes outputting at least a partially reconstructed version of the audio signal based at least in part on the first baseband signal and the second baseband signal.

High-band signal coding using multiple sub-bands

A device includes a receiver, a buffer, a transmitter, and an analyzer. The receiver is configured to receive a plurality of packets that corresponds to at least a subset of a sequence of packets. Error correction data of a first packet of the plurality of packets includes a partial copy of a second packet of the plurality of packets. The analyzer is configured to determine whether a particular packet of the sequence is missing from the buffer, and to determine whether a partial copy of the particular packet is stored in the buffer. The analyzer is also configured to send, via the transmitter, a retransmit message to a second device based at least in part on determining that the buffer does not store the particular packet and that the buffer does not store the partial copy of the particular packet.

System and method of redundancy based packet transmission error recovery

A particular method includes determining, based on an inter-line spectral pair (LSP) spacing corresponding to an audio signal, that the audio signal includes a component corresponding to an artifact-generating condition. The method also includes, in response to determining that the audio signal includes the component, adjusting a gain parameter corresponding to the audio signal. For example, the gain parameter may be adjusted via gain attenuation and/or gain smoothing.

Systems and methods of performing gain control

A method of processing an audio signal includes determining an average signal-to-noise ratio for the audio signal over time. The method includes, based on the determined average signal-to-noise ratio, a formant-sharpening factor is determined. The method also includes applying a filter that is based on the determined formant-sharpening factor to a codebook vector that is based on information from the audio signal.

A receiver is configured to receive packets that correspond to at least a subset of a sequence of packets and that include error correction data. The error correction data of a first packet of the packets includes a partial copy of a second packet. A buffer is configured to store the packets. An analyzer is configured to determine whether a first particular packet of the sequence is missing from the buffer, to determine whether a partial copy of the first particular packet is stored in the buffer as error correction data in a second particular packet, to update a value based at least in part on whether the first particular packet is missing from the buffer and the partial copy of the first particular packet is stored in the buffer, and to adjust an error recovery parameter based at least in part on the value.

A particular method includes determining, based on spectral information corresponding to an audio signal that includes a low-band portion and a high-band portion, that the audio signal includes a component corresponding to an artifact-generating condition. The method also includes filtering the high-band portion of the audio signal and generating an encoded signal. Generating the encoded signal includes determining gain information based on a ratio of a first energy corresponding to filtered high-band output to a second energy corresponding to the low-band portion to reduce an audible effect of the artifact-generating condition.

Systems and methods of performing filtering for gain determination

A particular method includes encoding a first frame of an audio signal using a first encoder. The method also includes generating, during encoding of the first frame, a baseband signal that includes content corresponding to a high band portion of the audio signal. The method further includes encoding a second frame of the audio signal using a second encoder, where encoding the second frame includes processing the baseband signal to generate high band parameters associated with the second frame.

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Venkatesh Krishnan