Abstract: In general, techniques are described by which to perform spatial relation coding using virtual higher order ambisonic coefficients. A device comprising a memory and a processor may perform the techniques. The memory may be configured to store audio data, the audio data representative of zero-ordered higher order ambisonic (HOA) coefficient, and one or more greater-than-zero-ordered HOA coefficients. The processor may be configured to obtain, based on the one or more greater-than-zero-ordered HOA coefficients, a virtual zero-ordered HOA coefficient. The processor may also be configured to obtain, based on the virtual HOA coefficient, one or more parameters from which to synthesize the one or more greater-than-zero-ordered HOA coefficients. The processor may further be configured to generate a bitstream that includes a first indication representative of the zero-ordered HOA coefficients, and a second indication representative of the one or more parameters.

Abstract: In general, techniques are described by which to perform spatial relation coding of higher order ambisonic coefficients using expanded parameters. A device comprising a memory and a processor may perform the techniques. The memory may be configured to store at least a portion of a bitstream, the bitstream including a first indication representative of an HOA coefficient associated with the spherical basis function having an order of zero, and a second indication representative of one or more parameters. The processor may be configured to perform parameter expansion with respect to the one or more parameters to obtain one or more expanded parameters, and synthesize, based on the one or more expanded parameters and the HOA coefficient associated with the spherical basis function having the order of zero, one or more HOA coefficients associated with one or more spherical basis functions having an order greater than zero.

Abstract: A device for processing audio data obtains data representing quantized versions of a set of one or more spatial vectors. Each respective spatial vector of the set of spatial vectors corresponds to a respective audio signal of the set of audio signals. Each of the spatial vectors is in a Higher-Order Ambisonics (HOA) domain and is computed based on a set of loudspeaker locations. The device inverse quantizes the quantized versions of the spatial vectors.

Abstract: In general, techniques are described for signaling layers for scalable coding of higher order ambisonic audio data. A device comprising a memory and a processor may be configured to perform the techniques. The memory may be configured to store the bitstream. The processor may be configured to obtain, from the bitstream, an indication of a number of layers specified in the bitstream, and obtain the layers of the bitstream based on the indication of the number of layers.

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: In a particular aspect, a multimedia device is configured to compensate for navigational movement within a visual environment. The multimedia device includes a processor configured to generate a first version of a spatialized audio signal of a sound field in a first audio frame based on a first position within a visual environment. The processor is configured to generate a second version of the spatialized audio signal of the sound field in a second audio frame based on compensating for the speed of movement of the multimedia device that indicates the first position within the visual environment changed to a second position within the visual environment, being different than the speed of movement in changing from a first location of the sound field to a second location of the sound field.

Abstract: In general, techniques are described for specifying audio rendering information in a bitstream. A device configured to generate the bitstream may perform various aspects of the techniques. The bitstream generation device may comprise one or more processors configured to specify audio rendering information that includes a signal value identifying an audio renderer used when generating the multi-channel audio content. A device configured to render multi-channel audio content from a bitstream may also perform various aspects of the techniques. The rendering device may comprise one or more processors configured to determine audio rendering information that includes a signal value identifying an audio renderer used when generating the multi-channel audio content, and render a plurality of speaker feeds based on the audio rendering information.

Abstract: An example device includes a memory device, and a processor coupled to the memory device. The memory is configured to store audio spatial metadata associated with a soundfield and video data. The processor is configured to identify one or more foreground audio objects of the soundfield using the audio spatial metadata stored to the memory device, and to select, based on the identified one or more foreground audio objects, one or more viewports associated with the video data. Display hardware coupled to the processor and the memory device is configured to output a portion of the video data being associated with the one or more viewports selected by the processor.

Abstract: An example device includes a memory device, and a processor coupled to the memory device. The memory is configured to store a plurality of representations of a soundfield. The processor is configured to track a steering angle provided by one or more angles associated with the device, and to select, based on the steering angle, a representation of the soundfield from the plurality of representations stored to the memory device.

Abstract: An apparatus includes a network interface configure to receive an audio bitstream. The audio bitstream includes encoded audio associated with one or more audio objects and audio metadata indicating one or more sound attributes of the one or more audio objects. The apparatus also includes a memory configured to store the encoded audio and the audio metadata. The apparatus further includes a controller configured to receive an indication to adjust a particular sound attribute of the one or more sound attributes. The particular sound attribute is associated with a particular audio object of the one or more audio objects. The controller is also configured to modify the audio metadata, based on the indication, to generate modified audio metadata.

Abstract: In general, techniques are described for signaling layers for scalable coding of higher order ambisonic audio data. A device comprising a memory and a processor may be configured to perform the techniques. The memory may be configured to store the bitstream. The processor may be configured to obtain, from the bitstream, an indication of a number of layers specified in the bitstream, and obtain the layers of the bitstream based on the indication of the number of layers.

Abstract: In general, techniques are described for performing layered intermediate compression for higher order ambisonic (HOA) audio data. A device comprising a memory and a processor may be configured to perform the techniques. The memory may store HOA coefficients of the HOA audio data. The processors may decompose the HOA coefficients into a predominant sound component and a corresponding spatial component. The spatial component may be representative of the directions, shape, and width of the predominant sound component, and defined in the spherical harmonic domain. The processor may specify, in a bitstream conforming to an intermediate compression format, a subset of the HOA coefficients that represent an ambient component. The processor may also specify, in the bitstream and irrespective of a determination of a minimum number of ambient channels and a number of elements to specify in the bitstream for the spatial component, all elements of the spatial component.

Abstract: A microphone device includes a microphone array configured to capture one or more audio objects associated with a three-dimensional sound field. The microphone array includes clusters of two or more microphone elements. Each cluster includes one or more acoustic port openings and two or more microphone elements coupled to the one or more acoustic port openings via corresponding acoustic ports. The microphone device also includes a processor coupled to the microphone array.

Abstract: A microphone device includes a microphone array configured to capture one or more audio objects associated with a three-dimensional sound field. The microphone array includes a first cluster and a second cluster. The first cluster includes a first set of two or more microphone elements and the second cluster includes a second set of two or more microphone elements. The microphone device also includes a processor coupled to the microphone array. The processor is configured to receive directionality information associated with a sound source. The processor is also configured to select a first microphone element configuration for the first cluster based on a condition, the directionality information, or both. Each microphone element of the first set of two or more microphone elements is deactivated in response to selection of the first microphone element configuration.

Abstract: In a particular aspect, a multimedia device includes one or more sensors configured to generate first sensor data and second sensor data. The first sensor data is indicative of a first position at a first time and the second sensor data is indicative of a second position at a second time. The multimedia device further includes a processor coupled to the one or more sensors. The processor is configured to generate a first version of a spatialized audio signal, determine a cumulative value based on an offset, the first position, and the second position, and generate a second version of the spatialized audio signal based on the cumulative value.

Abstract: In general, techniques are described by which to perform bitrate allocation with respect to higher order ambisonic (HOA) audio data. A device comprising a memory and a processor may be configured to perform various aspects of the bitrate allocation techniques. The memory may be configured to store a spatially compressed version of the HOA audio data. The processor may be coupled to the memory, and configured to perform bitrate allocation, based on an analysis of transport channels representative of the spatially compressed version of the HOA audio data, and prior to performing gain control with respect to the transport channels or after performing inverse gain control with respect to the transport channels, to allocate a number of bits to each of the transport channels. The processor may also be configured to generate a bitstream that specifies each of the transport channels using the respective allocated number of bits.

Abstract: Systems and techniques for rendering audio data are generally disclosed. An example device for rendering a higher order ambition (HOA) audio signal includes a memory configured to store the HOA audio signal, and one or more processors coupled to the memory. The one or more processors are configured to perform a loudness compensation process as part of generating an effect matrix. The one or more processors are further configured to render the HOA audio signal based on the effect matrix.

Abstract: An example audio decoding device includes processing circuitry and a memory device coupled to the processing circuitry. The processing circuitry is configured to receive, in a bitstream, encoded representations of audio objects of a three-dimensional (3D) soundfield, to receive metadata associated with the bitstream, to obtain, from the received metadata, one or more transmission factors associated with one or more of the audio objects, and to apply the transmission factors to the one or more audio objects to obtain parallax-adjusted audio objects of the 3D soundfield. The memory device is configured to store at least a portion of the received bitstream, the received metadata, or the parallax-adjusted audio objects of the 3D soundfield.

Abstract: In general, techniques are described for signaling channels for scalable coding of higher order ambisonic audio data. A device comprising a memory and a processor may be configured to perform the techniques. The memory may be configured to store the bitstream. The processor may be configured to obtain, from the bitstream, an indication of a number of channels specified in one or more layers in the bitstream, and obtain the channels specified in the one or more layers in the bitstream based on the indication of the number of channels.

Abstract: In general, techniques are described for determining quantization step sizes for compression of spatial components of a sound field. A device comprising one or more processors may be configured to perform the techniques. In other words, the one or more processors may be configured to determine a quantization step size to be used when compressing a spatial component of a sound field, where the spatial component generated by performing a vector based synthesis with respect to a plurality of spherical harmonic coefficients.