47 results about "Ambisonics" patented technology

A method for generating loudspeaker signals associated with a target screen size is disclosed. The method includes receiving a bit stream containing encoded higher order ambisonics signals, the encoded higher order ambisonics signals describing a sound field associated with a production screen size. The method further includes decoding the encoded higher order ambisonics signals to obtain a first set of decoded higher order ambisonics signals representing dominant components of the sound field and a second set of decoded higher order ambisonics signals representing ambient components of the sound field. The method also includes combining the first set of decoded higher order ambisonics signals and the second set of decoded higher order ambisonics signals to produce a combined set of decoded higher order ambisonics signals.

A time-of-flight (TOF) array including a plurality of cameras is positioned with a coplanar Higher Order Ambisonics (HOA) array including a plurality of microphones above a target area such as a room or space for analyzing speaker activity in that area. The HOA microphone array iteratively samples sound energy level frames captured by the microphones to identify a sound vector associated with the global maximum energy level in the sound energy level frame. This sound vector is fused with the data from the TOF camera array that identified the positions of sound sources in the target area to associate produced sound corresponding with the sound vector with a physical active sound source in the target area. A beamformer can then be used to save audio corresponding to the sound vector and discard audio not associated with the sound vector to produce a sound recording associated with the active sound source.

Methods and apparatus for acquiring and encoding omnidirectional surround sound are described herein. An exemplary omnidirectional surround microphone may include a first microphone capsule oriented substantially toward a first vertex of a conceptual tetrahedron, a second microphone capsule oriented substantially toward a second vertex of the conceptual tetrahedron, a third microphone capsule oriented substantially toward a third vertex of the conceptual tetrahedron and a fourth microphone capsule oriented substantially toward a fourth vertex of the conceptual tetrahedron.

The present document relates to a method of layered encoding of a frame of a compressed higher-order Ambisonics, HOA, representation of a sound or sound field. The compressed HOA representation comprises a plurality of transport signals. The method comprises assigning the plurality of transport signals to a plurality of hierarchical layers, the plurality of layers including a base layer and one or more hierarchical enhancement layers, generating, for each layer, a respective HOA extension payload including side information for parametrically enhancing a reconstructed HOA representation obtainable from the transport signals assigned to the respective layer and any layers lower than the respective layer, assigning the generated HOA extension payloads to their respective layers, and signaling the generated HOA extension payloads in an output bitstream. The present document further relates to a method of decoding a frame of a compressed HOA representation of a sound or sound field, an encoder and a decoder for layered coding of a compressed HOA representation, and a data structure representing a frame of a compressed HOA representation of a sound or sound field.

A decoding side method for spatial audio rendering using metadata, the method comprising: decoding a plurality of audio objects, a plurality of channels, or a high order ambisonics HOA representation

Higher Order Ambisonics represents three-dimensional sound independent of a specific loudspeaker set-up. However, transmission of an HOA representation results in a very high bit rate. Therefore, compression with a fixed number of channels is used, in which directional and ambient signal components are processed differently. The ambient HOA component is represented by a minimum number of HOA coefficient sequences. The remaining channels contain either directional signals or additional coefficient sequences of the ambient HOA component, depending on what will result in optimum perceptual quality. This processing can change on a frame-by-frame basis.

The invention relates to a panoramic sound space sound image positioning precision analysis method and device and electronic equipment. Comprising the following steps: determining sound image positioning positions, and acquiring an audio signal when a preset test audio is played at each sound image positioning position by using a head simulation audio acquisition device to obtain an audio signal pair of each sound image positioning position; calculating a time difference value and a sound pressure difference value of each position, and calculating an autopower spectrum of each audio signal pair by using Fourier transform; and carrying out region division on the spatial position and determining a weight, and obtaining a positioning precision analysis result according to a time difference value, a sound pressure difference value, a first autopower spectrum and a second autopower spectrum of each sound image positioning position and four parameter results of each position in a corresponding position in the ideal observer model. Therefore, the problems of consumption of a large amount of manpower and time cost, low precision, large result discreteness, difficulty in reproduction and the like in related technologies are solved, the influence of human subjective factors is eliminated, and the result has consistency, objectivity, stability and reproducibility.

An apparatus includes a memory configured to store first audio data and second audio data. The device also includes one or more processors coupled to the memory and configured to determine priorities of audio sources of the audio scene. The one or more processors are further configured to render the first audio data using the object renderer to generate a first audio signal. The first audio data represents a first audio source associated with a first priority. The one or more processors are further configured to render the second audio data using the first Ambisonics renderer to generate a second audio signal. The second audio data represents a second audio source associated with a second priority.

Dynamic range control (DRC) cannot be simply applied to higher-order ambisonics (HOA) based signals. [Solution] A method for performing DRC on an HOA signal includes converting the HOA signal to the spatial domain, analyzing the converted HOA signal, and obtaining a gain factor usable for dynamic compression from the results of the analysis. The gain factor can be transmitted together with the HOA signal. When DRC is applied, the HOA signal is converted to the spatial domain, the gain factor is extracted, and in the spatial domain, it is multiplied with the converted HOA signal to obtain a gain-compensated converted HOA signal. The gain-compensated converted HOA signal is converted back to the original HOA domain to obtain a gain-compensated HOA signal.

To provide a method and apparatus for improving the higher order ambisonics (HOA) compression.SOLUTION: An HOA compression method uses a given number of channels to separately process a directional signal component and an ambient signal component in the given number of channels. An ambient HOA component is expressed by a minimum number of HOA coefficient sequences. The remaining channels contain directional signals or additional coefficient sequences of the ambient HOA component depending on whether an optimal perception quality is yielded. The process can be changed in a frame unit.SELECTED DRAWING: Figure 1

A spatial audio restoration device of an embodiment includes a video feature amount calculation unit that calculates a video feature amount on the basis of video information, an audio feature amount calculation unit that calculates an audio feature amount on the basis of audio information that is a monaural sound corresponding to the video information, and a coefficient calculation unit that calculates a high-order Ambisonics coefficient on the basis of the video feature amount and the audio feature amount.

Disclosed is a hierarchical spatial resolution codec that adaptively adjusts the representations of immersive audio content as the target bandwidth for delivering the audio content changes. The audio content may be represented by an adaptive number of content types such as channels / objects, higher-order ambisonics (HOA), and encoded by adaptive spatial coding techniques to support the target bitrate of a transmission channel or user. Adaptive spatial coding techniques may include adaptive channel / object spatial encoding techniques to generate an adaptive number of channels / objects, and adaptive HOA spatial encoding or HOA compression techniques to generate an adaptive order of the HOA. The adaptation may be a function of the target bitrate that is associated with a desired quality, and an analysis that determines the priority of the channels, objects, and HOA. High priority channels / objects may be encoded into a high quality bit-stream while low priority channels / objects may be converted and encoded as HOA.

Decoding of Ambisonics representations for a stereo loudspeaker setup is known for first-order Ambisonics audio signals. But such first-order Ambisonics approaches have either high negative side lobes or poor localisation in the frontal region. The invention deals with the processing for stereo decoders for higher-order Ambisonics HOA. The desired panning functions can be derived from a panning law for placement of virtual sources between the loudspeakers. For each loudspeaker a desired panning function for all possible input directions at sampling points is defined. The panning functions are approximated by circular harmonic functions, and with increasing Ambisonics order the desired panning functions are matched with decreasing error. For the frontal region between the loudspeakers, a panning law like the tangent law or vector base amplitude panning (VBAP) are used. For the rear directions panning functions with a slight attenuation of sounds from these directions are defined.

The invention discloses a three-dimensional space sound playback method for a layered loudspeaker array. The three-dimensional space sound playback method comprises the following steps: presetting space coordinates of each unit of the loudspeaker array and a target virtual sound source; layering the loudspeaker array according to an elevation angle, calculating a two-dimensional Ambisonics decoding matrix for each layer of loudspeaker array, combining every two adjacent loudspeaker layers, and calculating an amplitude modulation inverse matrix; according to the elevation angle of the target virtual sound source, amplitude modulation coefficients of the loudspeaker layers combined in pairs are calculated, and effective loudspeaker layers are selected for playback; and synthesizing two virtual sources in the effective loudspeaker layer according to the azimuth angle of the target sound source, and synthesizing a three-dimensional virtual sound source in combination with horizontal azimuth angle decoding and amplitude modulation coefficients. According to the method, the playback precision of the area with the actual loudspeaker, especially the horizontal area, can be improved, and the requirements of the algorithm on the number of non-horizontal loudspeakers and the spatial uniformity are reduced.

A sound scene is represented as first order Ambisonics (FOA) audio. A processor formats each signal of the FOA audio to a stream of audio frames, provides the formatted FOA audio to a machine learning model that reformats the formatted FOA audio in a target or desired higher order Ambisonics (HOA) format, and obtains output audio of the sound scene in the desired HOA format from the machine learning model. The output audio in the desired HOA format may then be rendered according to a playback audio format of choice. Other aspects are also described and claimed.

To provide a method and apparatus for decoding an Ambisonics audio soundfield representation for audio playback using a 2D setup.SOLUTION: For decoding, a decode matrix specific to the given loudspeaker setup is needed, which is generated using the known loudspeaker positions. A method for decoding an encoded audio signal in a sound field format for L loudspeakers at known positions comprises the steps of adding 10 at least one virtual loudspeaker position to the L loudspeaker positions, generating 11 a 3D decoding matrix D ', downmixing 12 said 3D decoding matrix D ', and decoding 14 the encoded audio signal 3D using the downscaled i14 decoding matrix to obtain a plurality of decoded loudspeaker signals q14.SELECTED DRAWING: Figure 1

Conventional audio compression technologies perform a standardized signal transformation, independent of the type of the content. Multi-channel signals are decomposed into their signal components, subsequently quantized and encoded. This is disadvantageous due to lack of knowledge on the characteristics of scene composition, especially for e.g. multi-channel audio or Higher-Order Ambisonics (HOA) content. A method for decoding an encoded bitstream of multi-channel audio data and associated metadata is provided, including transforming the first Ambisonics format of the multi-channel audio data to a second Ambisonics format representation of the multi-channel audio data, wherein the transforming maps the first Ambisonics format of the multi-channel audio data into the second Ambisonics format representation of the multi-channel audio data. A method for encoding multi-channel audio data that includes audio data in an Ambisonics format, wherein the encoding includes transforming the audio data in an Ambisonics format into encoded multi-channel audio data is also provided.

To provide a method and an apparatus for decoding a stereo loudspeaker signal from a Higher Order Ambisonics (HOA) audio signal that achieves a good orientation in a forward direction and small negative sidelobes.SOLUTION: A method includes: a step 51 of calculating panning function to be desired which receives values of azimuth angles φL and φR of left and right loudspeakers and the number S of virtual sampling points, and calculates a matrix G comprising the panning function value to be described of all virtual sampling points; a step 52 of conducting the derives an order N from an Ambisonics signal a(t), calculates a mode matrix Z from the number S and the order N, and calculates a pseudo-inverse matrix +Z+ of the matrix Z; a step 53 of calculating mode matrix Ξ frim the number S and the order N; and a step 54 of calculating a pseudo-inverse matrix Ξ+ of the matrix Ξ. In a step 55, a decoding matrix D from the matrix G and a Ξ+ is calculated, and in a step 56, a loudspeaker signal l(t) is calculated from the Ambisonics signal a(t) by using the decoding matrix D.SELECTED DRAWING: Figure 5

Described techniques enable the use of ambisonics encoding / decoding for spatially accurate sound reproduction that is low-latency and that conserves computational and battery resources. Different sounds sources may be encoded using different ambisonics encoding orders, with higher order encoding being used to process sound from a sound source of current attention of a user, and lower order encoding being used to process other sound sources, such as background sound sources.

The present document describes a method (400) for rendering an Ambisonics signal using a loudspeaker arrangement including S loudspeakers. The method (400) includes converting (401) a set of N Ambisonics channel signals (111) into a set of unfiltered pre-rendered signals (211), where N>1 and S>1. The method (400) further includes performing near-field compensation (referred to as NFC) filtering (402) of M unfiltered pre-rendered signals (211) of the set of unfiltered pre-rendered signals (211) to provide a set of S filtered loudspeaker channel signals (114) for rendering using the corresponding S loudspeakers.

A method including receiving an audio signal including a plurality of audio channels, selecting a first portion of the plurality of audio channels, selecting a second portion of the plurality of audio channels, generating first mixed audio channels by mixing the first portion of the plurality of audio channels with a first time-delayed audio channel, generating second mixed audio channels by mixing the second portion of the plurality of audio channels with a second time-delayed audio channel, and generating an augmented ambisonics model based on the plurality of audio channels, the first mixed audio channels, and the second mixed audio channels.

Make it possible to obtain a pseudo acoustic intensity vector using an acoustic signal collected by a wearable device. To this end, a pseudo-ambisonics signal generating apparatus according to the disclosed technology includes a spherical coordinate acquisition unit, a calculation unit, and a signal extraction unit. The spherical coordinate acquisition unit acquires spherical coordinates of each microphone with an intersection of a plane dividing a face symmetrically to the left and right and a straight line passing through the centers of left and right ears as an origin. The calculation unit calculates an average value of radii of the spherical coordinates, and replaces the radii of the spherical coordinates with the average values. The signal extraction unit generates a pseudo-ambisonics signal using the spherical coordinates replaced with the average values and acoustic signals acquired by the microphones.

A method that includes receiving a higher-order ambisonics (HOA) representation of a sound field that includes a first plurality of audio signals, separating a second plurality of audio signals from the first plurality of audio signals that are associated with a first-order ambisonics (FOA) representation of the sound field, determining a plurality of adaptive filters based on at least some of the second plurality of audio signals, producing a plurality of output audio signals based on the first plurality of audio signals and the plurality of adaptive filters, each output audio signal having at least a portion of the sound field, and driving a plurality of speakers using the plurality of output audio signals.

An apparatus for generating binaural audio based on a listener position within an audio scene, the apparatus comprising means configured to: obtain, for at least one audio source at least one audio source position from the audio scene; obtain a listener position within the audio scene, wherein the audio scene comprises: at least one internal region; and at least one external region, the regions defined with respect to the at least one audio source position; determine whether the listener position is located within the at least one internal region or at least one external region; determine whether the at least one audio source is available for rendering based on the determined listener position; determine a rendering mode based on the determination of the at least one audio source is available for rendering based on the determined listener position and whether the listener position is located within the at least one internal region or at least one external region; and render the binaural audio signal based on the determined rendering mode.

The invention improves HOA sound field representation compression and decompression. A decoder decodes compressed dominant directional signals and compressed residual component signals so as to provide decompressed dominant directional signals and decompressed time domain signals representing a residual HOA component in a spatial domain. A re-correlator re-correlates the decompressed time domain signals to obtain a corresponding reduced-order residual HOA component. A processor determines a decompressed residual HOA component based on the corresponding reduced-order residual HOA component, and determines predicted directional signals based on at least a parameter. The processor is further configured to determine an HOA sound field representation based on the decompressed dominant directional signals, the predicted directional signals, and the decompressed residual HOA component.

To provide a method and device for compressing and decompressing higher-order ambisonic representations that process directional and ambient components in different formats.SOLUTION: A compression method performs the process of estimating a dominant direction and decomposing an ambisonics signal C(l) into directional and ambient components in a dominant direction estimation section 22. I(L) indicates a frame index. The directional component is calculated in the directional signal calculation step or stage 23, the ambisonics representation is transformed into a time domain signal represented by a set of D normal directional signals X(l) and the corresponding direction, and the residual ambient component is calculated in an ambient HOA component calculation step or stage 24, is expressed by the HOA domain coefficients CA(l), and compression is performed. After that, it is order-extended to reconstruct the complete HOA representation from the direction signal, corresponding direction information and the ambient HOA components of an original order.SELECTED DRAWING: Figure 2

To provide a method for decoding a compressed higher-order ambisonics (HOA) representation of sound or sound fields.SOLUTION: A method includes the steps of: receiving a bitstream containing a compressed HOA representation; determining the highest available layer among multiple layers for decoding; extracting HOA extended payload assigned to the highest available layer; decoding the compressed HOA representation corresponding to the highest available layer, based on layer information and a transport signal assigned to the highest available layer and arbitrary layers lower than the highest available layer; and parametrically enhancing the decoded HOA representation using the side information included in the HOA extension payload assigned to the highest available layer.SELECTED DRAWING: Figure 5