Qualcomm Incorporated

Apple Inc.

Moo Young Kim

Dipanjan Sen

Nils Günther Peters

S M Akramus Salehin

Shankar Thagadur Shivappa

Siddhartha Goutham Swaminathan

Frank M Baumgarte

Isaac Garcia Munoz

Ferdinando Olivieri

Sina Zamani

Thomas Stockhammer

Aram M Lindahl

Eric A Allamanche

Nils Gunther Peters

Jason Filos

Richard Paul Walters

Eric J Day

Jeongook Song

J Kevin Calhoun

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.

Hierarchical spatial resolution codec

Disclosed are methods and systems for decoding immersive audio content encoded by an adaptive number of scene elements for channels, audio objects, higher-order ambisonics (HOA), and/or other sound field representations. The decoded audio is rendered to the speaker configuration of a playback device. For bit streams that represent audio scenes with a different mixture of channels, objects, and/or HOA in consecutive frames, fade-in of the new frame and fade-out of the old frame may be performed. Crossfading between consecutive frames happen in the speaker layout after rendering, in the spatially decoded content type before rendering, or between the transport channels as the output of the baseline decoder but before spatial decoding and rendering. Crossfading may use an immediate fade-in and fade-out frame (IFFF) for the transition frame or may use an overlap-add synthesis technique such as time-domain aliasing cancellation (TDAC) of MDCT.

Seamless scalable decoding of channels, objects, and HOA audio content

An example audio decoding device includes a memory configured to store at least a portion of a coded audio bitstream; and one or more processors configured to: decode, based on the coded audio bitstream, a representation of a soundfield; decode, based on the coded audio bitstream, a syntax element indicating a selection of either a head-related transfer function (HRTF) or a binaural room impulse response (BRIR); and render, using the selected HRTF or BRIR, speaker feeds from the soundfield.

Signaling for rendering tools

A device and method for backward compatibility for virtual reality (VR), mixed reality (MR), augmented reality (AR), computer vision, and graphics systems. The device and method enable rendering audio data with more degrees of freedom on devices that support fewer degrees of freedom. The device includes memory configured to store audio data representative of a soundfield captured at a plurality of capture locations, metadata that enables the audio data to be rendered to support N degrees of freedom, and adaptation metadata that enables the audio data to be rendered to support M degrees of freedom. The device also includes one or more processors coupled to the memory, and configured to adapt, based on the adaptation metadata, the audio data to provide the M degrees of freedom, and generate speaker feeds based on the adapted audio data.

Six degrees of freedom and three degrees of freedom backward compatibility

In general, techniques are described for obtaining audio rendering information from a bitstream. A method of rendering audio data includes receiving, at an interface of a device, an encoded audio bitstream, storing, to a memory of the device, encoded audio data of the encoded audio bitstream, parsing, by one or more processors of the device, a portion of the encoded audio data stored to the memory to select a renderer for the encoded audio data, the selected renderer comprising one of an object-based renderer or an ambisonic renderer, rendering, by the one or more processors of the device, the encoded audio data using the selected renderer to generate one or more rendered speaker feeds, and outputting, by one or more loudspeakers of the device, the one or more rendered speaker feeds.

Flexible rendering of audio data

A device configured to decode a bitstream, where the device includes a memory configured to store a temporally encoded representation of spatial audio signals. The device is also configured to receive the bitstream that includes an indication of a spatial transformation, and includes a temporal decoding unit, coupled to the memory, configured to decode one or more spatial audio signals represented in a spatial domain, where the one or more spatial audio signals are associated with different angles in the spatial domain. In addition, the device includes an inverse spatial transformation unit, coupled to the temporal decoding unit, is configured to convert the one or more spatial audio signals represented in the spatial domain into at least three ambisonic coefficients that, in part, represent a soundfield in an ambisonics domain, and perform a spatial transformation of the soundfield based on the indication of the spatial transformation received in the bitstream.

Spatial transformation of ambisonic audio data

In general, techniques are described by which to provide priority information for higher order ambisonic (HOA) audio data. A device comprising a memory and a processor may perform the techniques. The memory stores HOA coefficients of the HOA audio data, the HOA coefficients representative of a soundfield. The processor may decompose the HOA coefficients into a sound component and a corresponding spatial component, the corresponding spatial component defining shape, width, and directions of the sound component, and the corresponding spatial component defined in a spherical harmonic domain. The processor may also determine, based on one or more of the sound component and the corresponding spatial component, priority information indicative of a priority of the sound component relative to other sound components of the soundfield, and specify, in a data object representative of a compressed version of the HOA audio data, the sound component and the priority information.

Higher order ambisonic audio data

One or more processors may obtain a first distance between a first audio zone of the two or more audio zones associated with the one or more interest points within the first audio zone, and a first device position of a device, obtain a second distance between a second audio zone of the two or more audio zones associated with the one or more interest points within the second audio zone, and the first device position of the device, and obtain an updated first distance and updated second distance after movement of the device has changed from the first device position to a second device position. The one or more processor(s) may independently control the first audio zone and the second audio zone, such that the audio data within the first audio zone and the second audio zone are adjusted based on the updated first distance and updated second distance.

Rendering audio data from independently controlled audio zones

In general, techniques are described for rendering metadata to control user movement based audio rendering. A device comprising a memory and one or more processors may be configured to perform the techniques. The memory may be configured to store audio data representative of a soundfield. The one or more processors may be coupled to the memory, and configured to obtain rendering metadata indicative of controls for enabling or disabling adaptations, based on an indication of a movement of a user of the device, of a renderer used to render audio data representative of a soundfield, specify, in a bitstream representative of the audio data, the rendering metadata, and output the bitstream.

Rendering metadata to control user movement based audio rendering

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.

Signaling layers for scalable coding of higher order ambisonic audio data

In general, techniques are described for modeling occlusions when rendering audio data. A device comprising a memory and one or more processors may perform the techniques. The memory may store audio data representative of a soundfield. The one or more processors may obtain occlusion metadata representative of an occlusion within the soundfield in terms of propagation of sound through the occlusion, the occlusion separating the soundfield into two or more sound spaces. The one or more processors may obtain a location of the device, and obtain, based on the occlusion metadata and the location, a renderer by which to render the audio data into one or more speaker feeds that account for propagation of the sound in one of the two or more sound spaces in which the device resides. The one or more processors may apply the renderer to the audio data to generate the speaker feeds.

Representing occlusion when rendering for computer-mediated reality systems

In general, techniques are described by which to embed enhanced audio transports in backward compatible 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, which 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 obtain, from the backward compatible bitstream, extended audio data that enhances the legacy audio data. The processor(s) may also obtain, based on the legacy audio data and the extended audio data, enhanced audio data that conforms to an enhanced audio format, and output the enhanced audio data to one or more speakers.

Embedding enhanced audio transports in backward compatible audio bitstreams

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.

Spatially formatted enhanced audio data for backward compatible audio bitstreams

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.

Growing community of inventors

San Diego, CA, United States of America

Moo Young Kim