Abstract: A method includes decoding a low-band portion of an encoded mid channel to generate a decoded low-band mid channel. The method also includes filtering the decoded low-band mid channel according to one or more filter coefficients to generate a low-band filtered mid channel. The method also includes generating an inter-channel predicted signal based on the low-band filtered mid channel and the inter-channel prediction gain. The method further includes generating a low-band left channel and a low-band right channel based on an up-mix factor, the decoded low-band mid channel, and the inter-channel predicted signal.

Abstract: A method includes generating a synthesized non-reference high-band channel based on a non-reference high-band excitation corresponding to a non-reference target channel. The method further includes estimating one or more spectral mapping parameters based on the synthesized non-reference high-band channel and a high-band portion of the non-reference target channel. The method also includes applying the one or more spectral mapping parameters to the synthesized non-reference high-band channel to generate a spectrally shaped synthesized non-reference high-band channel. The method further includes generating an encoded bitstream based on the one or more spectral mapping parameters and the spectrally shaped synthesized non-reference high-band channel.

Abstract: A method for multi-channel audio or speech signal processing includes receiving a reference channel and a target channel, determining a variation between a first mismatch value and a second mismatch value, and comparing the variation with a first threshold that may have a pre-determined value or may be adjusted based on a frame type or a smoothing factor. The method also includes adjusting a set of target samples of the target channel based on the variation and based on the comparison to generate an adjusted set of target samples. Adjusting the set of target samples includes selecting one among a first interpolation and a second interpolation based on the variation. The method further includes generating at least one encoded channel based on a set of reference samples and the adjusted set of target samples. The method also includes transmitting the at least one encoded channel to a second device.

Abstract: A method includes receiving, at an audio encoder, multiple streams of audio data, where N is the number of the received multi streams. The method includes determining a similarity value for each stream of the multiple streams and comparing the similarity value for each stream of the multiple streams with a threshold. The method also includes identifying, based on the comparison, L (L<N) number of streams to be encoded among the N number of the multiple streams. The method includes encoding the identified L number of streams to generate an encoded bitstream.

Abstract: A method includes performing modifying, at a decoder, at least a portion of inter-channel phase difference (IPD) parameter values based on a mismatch value to generate modified IPD parameter values. The mismatch value is indicative of an amount of temporal misalignment between an encoder-side reference channel and an encoder-side target channel. The modified IPD parameter values are applied to a decoded frequency-domain mid channel during an up-mix operation.

Abstract: A device for signal processing with a receiver that receives an encoded audio signal comprising a parameter, and based on the value of parameter selects one non-linear processing function for generating a first excitation signal, a second non-linear processing function for generating a second excitation signal, and generates a high-band excitation signal based on the first excitation signal and second excitation signal.

Abstract: A device includes a receiver and a decoder. The receiver is configured to receive bitstream parameters corresponding to at least an encoded mid signal. The decoder is configured to generate a synthesized mid signal based on the bitstream parameters. The decoder is also configured to generate one or more upmix parameters. An upmix parameter of the one or more upmix parameters having a first value or a second value based on determining whether the bitstream parameters correspond to an encoded side signal. The first value is based on a received downmix parameter. The second value is based at least in part on a default parameter value. The decoder is further configured to generate an output signal based on the synthesized mid signal and the one or more upmix parameters.

Abstract: A device includes a multi-channel encoder configured to receive a first audio signal and a second audio signal, to perform a downmix operation on the first audio signal and the second audio signal to generate a mid signal, to generate a low-band mid signal and a high-band mid signal based on the mid signal, and to determine, based at least partially on a low band voicing value corresponding to the low band signal and a gain value corresponding to the high-band mid signal, a value of a multi-source flag that flag associated with the high-band mid signal. The multi-channel encoder is configured to generate a high-band mid excitation signal based on the multi-source flag and to generate a bitstream based on the high-band mid excitation signal. The device also includes a transmitter configured to transmit the bitstream and the multi-source flag to a second device.

Abstract: An apparatus includes a receiver and a decoder. The receiver is configured to receive a bitstream that includes a first frame and a second frame. The first frame includes a first portion of a mid channel and a first quantized stereo parameter. The second frame includes a second portion of the mid channel and a second quantized stereo parameter. The decoder is configured to generate a first portion of a channel based on the first portion of the mid channel and the first quantized stereo parameter. The decoder is configured to, in response to the second frame being unavailable for decoding operations, estimate the second quantized stereo parameter based on stereo parameters of one or more preceding frames and generate a second portion of the channel based on the estimated second quantized stereo parameter. The second portion of the channel corresponds to a decoded version of the second frame.

Abstract: An apparatus includes a receiver and an up-mixer. The receiver is configured to receive a bitstream that includes an encoded mid signal and encoded stereo parameter information. The encoded stereo parameter information represents a first value of a stereo parameter and a second value of the stereo parameter. The first value is associated with a first frequency range. The second value is associated with a second frequency range that is distinct from the first frequency range. The up-mixer is configured to perform an up-mix operation on a frequency-domain decoded mid signal generated from the encoded mid signal. A particular value based on the first value and the second value is applied to the frequency-domain decoded mid signal during the up-mix operation.

Abstract: An apparatus includes a receiver and a decoder. The receiver is configured to receive a bitstream that includes an encoded mid channel and a quantized value representing a shift between a reference channel associated with an encoder and a target channel associated with the encoder. The quantized value is based on a value of the shift. The value of the shift is associated with the encoder and has a greater precision than the quantized value. The decoder is configured to decode the encoded mid channel to generate a decoded mid channel and to generate a first channel based on the decoded mid channel. The decoder is further configured to generate a second channel based on the decoded mid channel and the quantized value. The first channel corresponds to the reference channel and the second channel corresponds to the target channel.

Abstract: A device includes a receiver configured to receive an audio frame of an audio stream. The audio frame includes information that indicates a coded bandwidth of the audio frame. The device also includes a decoder configured to generate first decoded speech associated with the audio frame and to determine an output mode of the decoder based at least in part on the information that indicates the coded bandwidth. A bandwidth mode indicated by the output mode of the decoder is different than a bandwidth mode indicated by the information that indicates the coded bandwidth. The decoder is further configured to output second decoded speech based on the first decoded speech. The second decoded speech is generated according to an output mode of the decoder.

Abstract: A stereo parameter conditioner performs a conditioning operation on a first value of a stereo parameter and a second value of the stereo parameter to generate a conditioned value of the stereo parameter. The first value is associated with a first frequency range, and the second value is associated with a second frequency range. The conditioned value is associated with a particular frequency range that is a subset of the first frequency range or a subset of the second frequency range.

Abstract: A method of encoding audio channels includes receiving two or more channels at an encoder and identifying a target channel and a reference channel. The target channel and the reference channel are identified from the two or more channels based on a mismatch value. The method also includes generating a modified target channel by temporally adjusting the target channel based on the mismatch value. The mismatch value is indicative of an amount of temporal mismatch between the target channel and the reference channel. The method also includes determining a temporal correlation value indicative of a temporal correlation between a first signal associated with the reference channel and a second signal associated with the modified target channel. The method also includes comparing the temporal correlation value to a threshold. The method further includes generating missing target samples based on the comparison, a coder type, or both.

Abstract: An apparatus includes a receiver configured to receive at least one encoded signal that includes inter-channel bandwidth extension (BWE) parameters. The device includes a decoder configured to generate a mid-channel time-domain high-band signal by performing bandwidth extension based on the at least one encoded signal. The decoder is configured to generate, based on the mid-channel time-domain high-band signal and the inter-channel BWE parameters, a first channel time-domain high-band signal and a second channel time-domain high-band signal. The first channel time-domain high-band signal is selectively based on an adjustment spectral shape parameter responsive to whether the inter-channel BWE parameters include an adjustment spectral shape parameter. The decoder is configured to generate a target channel signal based at least in part on the first channel time-domain high-band signal, and to generate a reference channel signal based at least in part on the second channel time-domain high-band signal.

Abstract: A device includes an encoder configured to determine, during a first period, that a first audio signal is a leading signal and that a second audio signal is a lagging signal. The encoder is also configured to generate a first frame of at least one encoded signal based on a first modified version of the second audio signal that is generated by adjusting the second audio signal based on a first mismatch value. The encoder is configured to determine, during a second period, that the first audio signal is the leading signal and that the second audio signal is the lagging signal. The encoder is configured to generate a second frame of the at least one encoded signal based on a second modified version of the second audio signal that is generated by adjusting the second audio signal based on the first mismatch value and a second mismatch value.

Abstract: A device for processing audio signals includes an interchannel phase difference (IPD) mode selector and an IPD estimator. The IPD mode selector is configured to select an IPD mode based on at least a strength value associated with a temporal misalignment between a first audio signal and a second audio signal. The IPD estimator is configured to determine IPD values based on the first audio signal and the second audio signal. The IPD values have a resolution corresponding to the selected IPD mode.

Abstract: A device includes a processor that is configured to determine an inter-channel mismatch value indicative of a temporal misalignment between a frequency-domain reference channel and a frequency-domain target channel. The processor is also configured to adjust the frequency-domain target channel based on the inter-channel mismatch value to generate an adjusted frequency-domain target channel. The processor is further configured to perform a down-mix operation, based on the frequency-domain reference channel and the adjusted frequency-domain target channel, to generate a mid channel and a side channel. The processor is also configured to generate a predicted side channel based on the mid channel. The processor is further configured to generate a residual channel based on the side channel and the predicted side channel. The processor is also configured to encode the residual channel as part of a bitstream.

Abstract: A device for processing audio signals includes an interchannel phase difference (IPD) mode selector and an IPD estimator. The IPD mode selector is configured to select an IPD mode from among at least a first IPD mode and a second IPD mode based on at least an interchannel temporal mismatch value indicative of a temporal misalignment between a first audio signal and a second audio signal. The IPD estimator is configured to determine IPD values based on the first audio signal and the second audio signal, the IPD values represented using a first number of bits responsive to selection of the first IPD mode or represented using a second number of bits responsive to selection of the second IPD mode.

Abstract: A device includes an encoder configured to determine, during a first period, that a first audio signal is a leading signal and that a second audio signal is a lagging signal. The encoder is also configured to generate a first frame of at least one encoded signal based on a first modified version of the second audio signal that is generated by adjusting the second audio signal based on a first mismatch value. The encoder is configured to determine, during a second period, that the first audio signal is the leading signal and that the second audio signal is the lagging signal. The encoder is configured to generate a second frame of the at least one encoded signal based on a second modified version of the second audio signal that is generated by adjusting the second audio signal based on the first mismatch value and a second mismatch value.