Abstract: A device includes one or more processors configured to, during a call, receive a sequence of audio frames from a first device. The one or more processors are configured to, in response to determining that no audio frame of the sequence has been received for a threshold duration since a last received audio frame of the sequence, initiate transmission of a frame loss indication to the first device. The one or more processors are also configured to, responsive to the frame loss indication, receive a set of audio frames of the sequence and an indication of a second playback speed from the first device. The one or more processors are configured to initiate playback, via a speaker, of the set of audio frames based on the second playback speed. The second playback speed is greater than a first playback speed of a first set of audio frames of the sequence.

Abstract: In general, techniques are described by which to code scaled spatial components. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store a bitstream including an encoded foreground audio signal and a corresponding quantized spatial component. The one or more processors may perform psychoacoustic audio decoding with respect to the encoded foreground audio signal to obtain a foreground audio signal, and determine, when performing psychoacoustic audio decoding, a bit allocation for the encoded foreground audio signal. The one or more processors may dequantize the quantized spatial component to obtain a scaled spatial component, and descale, based on the bit allocation, the scaled spatial component to obtain a spatial component. The one or more processors may reconstruct, based on the foreground audio signal and the spatial component, scene-based audio data.

Abstract: An example device configured to obtain image data includes a memory configured to store one or more priority values, each of the one or more priority values being associated with a type of image object associated with the image data. The device includes one or more processors coupled to the memory, and configured to associate image objects in the image data with one or more audio sources represented in one or more audio streams. The one or more processors are also configured to assign a respective priority value to each of the one or more audio sources represented in the one or more streams and code ambisonic coefficients based on the assigned priority value.

Abstract: An example device includes a memory configured to store at least one spatial component and at least one audio source within a plurality of audio streams. The device also includes one or more processors coupled to the memory. The one or more processors are configured to receive, from motion sensors, rotation information. The one or more processors are configured to rotate the at least one spatial component based on the rotation information to form at least one rotated spatial component. The one or more processors are also configured to reconstruct ambisonic signals from the at least one rotated spatial component and the at least one audio source, wherein the at least one spatial component describes spatial characteristics associated with the at least one audio source in a spherical harmonic domain representation.

Abstract: In general, techniques are described by which to specify spatially formatted enhanced audio data for backward compatible audio bitstreams. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store the backward compatible bitstream that conforms to a legacy transport format. The processor(s) may obtain, from the backward compatible bitstream, legacy audio data that conforms to a legacy audio format and a spatially formatted extended audio stream. The processor(s) may process the spatially formatted extended audio stream to obtain extended audio data that enhances the legacy audio data. The processor(s) may next obtain, based on the legacy audio data and the extended audio data, enhanced audio data that conforms to an enhanced audio format. The processor(s) may output the enhanced audio data to one or more speakers.

Abstract: An example device configured to obtain image data includes a memory configured to store one or more priority values, each of the one or more priority values being associated with a type of image object associated with the image data. The device includes one or more processors coupled to the memory, and configured to associate image objects in the image data with one or more audio sources represented in one or more audio streams. The one or more processors are also configured to assign a respective priority value to each of the one or more audio sources represented in the one or more streams and code ambisonic coefficients based on the assigned priority value.

Abstract: An example device includes a memory configured to store at least one spatial component and at least one audio source within a plurality of audio streams. The device also includes one or more processors coupled to the memory. The one or more processors are configured to receive, from motion sensors, rotation information. The one or more processors are configured to rotate the at least one spatial component based on the rotation information to form at least one rotated spatial component. The one or more processors are also configured to reconstruct ambisonic signals from the at least one rotated spatial component and the at least one audio source, wherein the at least one spatial component describes spatial characteristics associated with the at least one audio source in a spherical harmonic domain representation.

Abstract: In general, techniques are described by which to render different portions of audio data using different renderers. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store audio renderers. The processor(s) may obtain a first audio renderer of the plurality of audio renderers, and apply the first audio renderer with respect to a first portion of the audio data to obtain one or more first speaker feeds. The processor(s) may next obtain a second audio renderer of the plurality of audio renderers, and apply the second audio renderer with respect to a second portion of the audio data to obtain one or more second speaker feeds. The processor(s) may output, to one or more speakers, the one or more first speaker feeds and the one or more second speaker feeds.

Abstract: In general, techniques are described by which to correlate scene-based audio data for psychoacoustic audio coding. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store a bitstream including a plurality of encoded correlated components of a soundfield represented by scene-based audio data. The one or more processors may perform psychoacoustic audio decoding with respect to one or more of the plurality of encoded correlated components to obtain a plurality of correlated components, and obtain, from the bitstream, an indication representative of how the one or more of the plurality of correlated components were reordered in the bitstream. The one or more processors may reorder, based on the indication, the plurality of correlated components to obtain a plurality of reordered components, and reconstruct, based on the plurality of reordered components, the scene-based audio data.

Abstract: In general, techniques are described for psychoacoustic audio coding of ambisonic audio data. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store the bitstream that includes an encoded audio object and a corresponding spatial component that defines spatial characteristics of the encoded foreground audio signal. The encoded foreground audio signal may include a coded gain and a coded shape. The one or more processors may perform a gain and shape synthesis with respect to the coded gain and the coded shape to obtain a foreground audio signal, and reconstruct, based on the foreground audio signal and the spatial component, the ambisonic audio data.

Abstract: In general, techniques are described for quantizing spatial components based on bit allocations determined for psychoacoustic audio coding. A device comprising a memory and one or more processors may perform the techniques. The memory may store a bitstream including an encoded foreground audio signal and a corresponding quantized spatial component. The one or more processors may perform psychoacoustic audio decoding with respect to the encoded foreground audio signal to obtain a foreground audio signal, and determine, when performing the psychoacoustic audio decoding, a first bit allocation for the encoded foreground audio signal. The one or more processors may also determine, based on the first bit allocation, a second bit allocation, and dequantize, based on the second bit allocation, the quantized spatial component to obtain a spatial component. The one or more processors may reconstruct, based on the foreground audio signal and the spatial component, scene-based audio data.

Abstract: In general, techniques are described by which to code scaled spatial components. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store a bitstream including an encoded foreground audio signal and a corresponding quantized spatial component. The one or more processors may perform psychoacoustic audio decoding with respect to the encoded foreground audio signal to obtain a foreground audio signal, and determine, when performing psychoacoustic audio decoding, a bit allocation for the encoded foreground audio signal. The one or more processors may dequantize the quantized spatial component to obtain a scaled spatial component, and descale, based on the bit allocation, the scaled spatial component to obtain a spatial component. The one or more processors may reconstruct, based on the foreground audio signal and the spatial component, scene-based audio data.

Abstract: In general, various aspects of the techniques described in this disclosure are directed to performing psychoacoustic audio coding based on operating conditions. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may be configured to store the encoded scene-based audio data. The one or more processors may be configured to obtain an operating condition of the device for decoding the encoded scene-based audio data and perform, based on the operating condition, psychoacoustic audio decoding with respect to the encoded scene-based audio data to obtain ambisonic transport format audio data. The one or more processors may also be configured to perform spatial audio decoding with respect to the ambisonic transport format audio data to obtain scene-based audio data.

Abstract: In general, techniques are described for recursively defined audio metadata. A device comprising one or more memories and one or more processors may be configured to perform various aspects of the techniques. The one or more memories may store at least a portion of the bitstream. The one or more processors may obtain, from the bitstream, recursively defined audio metadata, and obtain, from the bitstream, a representation of the audio data. The one or more processors may process, based on the recursively defined audio metadata, the representation of the audio data to obtain one or more speaker feeds, and output the one or more speaker feeds to one or more speakers.

Abstract: In general, techniques are described by which to synchronize enhanced audio transports with backward compatible audio transports. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store a backward compatible bitstream conforming to a legacy transport format. The processor may obtain, from the backward compatible bitstream, a first audio transport stream, and obtain, from the backward compatible bitstream, a second audio transport stream. The processor(s) may also obtain, from the backward compatible bitstream, indications representative of synchronization information for the first audio transport stream and the second audio transport stream. The processor(s) may synchronize, based on the indications, the first audio transport stream and the second audio transport to obtain synchronized audio data stream.

Abstract: In general, techniques are described by which to obtain demixing data for backward compatible rendering of higher order ambisonic audio data. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store the higher order ambisonic (HOA) audio data. The processor may obtain, from a bitstream, legacy audio data that conforms to a legacy audio format, and obtain, from the bitstream, de-mixing data. The processor(s) may process, based on the de-mixing data, the legacy audio data to obtain the first portion of the HOA audio data. The processor(s) may next obtain, from the bitstream, a second portion of the HOA audio data. The processor(s) may render the first portion and the second portion to obtain a speaker feed. Further, the processor(s) may output the speaker feed to a speaker to reproduce a soundfield represented by the HOA audio data.

Abstract: In general, techniques are described by which to render different portions of audio data using different renderers. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store audio renderers. The processor(s) may obtain a first audio renderer of the plurality of audio renderers, and apply the first audio renderer with respect to a first portion of the audio data to obtain one or more first speaker feeds. The processor(s) may next obtain a second audio renderer of the plurality of audio renderers, and apply the second audio renderer with respect to a second portion of the audio data to obtain one or more second speaker feeds. The processor(s) may output, to one or more speakers, the one or more first speaker feeds and the one or more second speaker feeds.

Abstract: In general, techniques are described by which to specify spatially formatted enhanced audio data for backward compatible audio bitstreams. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may store the backward compatible bitstream that conforms to a legacy transport format. The processor(s) may obtain, from the backward compatible bitstream, legacy audio data that conforms to a legacy audio format and a spatially formatted extended audio stream. The processor(s) may process the spatially formatted extended audio stream to obtain extended audio data that enhances the legacy audio data. The processor(s) may next obtain, based on the legacy audio data and the extended audio data, enhanced audio data that conforms to an enhanced audio format. The processor(s) may output the enhanced audio data to one or more speakers.

Abstract: A method includes performing, at a processor, signal processing operations on signals captured by each microphone in a microphone array. The method also includes performing a first directivity adjustment by applying a first set of multiplicative factors to the signals to generate a first set of ambisonic signals. The first set of multiplicative factors is determined based on a position of each microphone in the microphone array, an orientation of each microphone in the microphone array, or both.

Abstract: The disclosure relates to an apparatus for generating a sound field on the basis of an input audio signal. The apparatus comprises a plurality of transducers, wherein each transducer is configured to be driven by a transducer driving signal ql of the respective transducer; a plurality of filters configured to generate for each transducer the transducer driving signal ql of the respective transducer; and a control unit configured to provide or receive a first transducer driving signal vector q0 of dimension L such that the gradient of J(q;?) with respect to q is zero in (q0;?0), the control unit is further configured to provide a second transducer driving signal vector {tilde over (q)} of dimension L such that the gradient of the cost function J(q;?) with respect to q is [approximately] zero in ({tilde over (q)}; {tilde over (?)}), the control unit is configured to provide the second transducer driving signal vector {tilde over (q)}.