Spatial Audio Direction Transform for Low-Bitrate Parameter Encoding
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Solution Overview
Problem
Existing spatial audio encoding technologies face challenges in efficiently compressing spatial audio parameters, particularly when dealing with multiple sound sources in a scene, leading to high bit rates that exceed the available bitrate for immersive audio communications.
Innovation Solution
A method and apparatus that transform spatial audio direction parameters by aligning sound source directions within a time-frequency tile, applying a rotational transformation to reduce variance and improve quantization efficiency, followed by encoding these parameters for efficient bit representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If binaural recordings are used to preserve spatial audio information, then spatial realism is improved, but compatibility with monophonic playback devices deteriorates
Solution Approach 1:
The system dynamically adjusts audio parameters based on playback conditions. The transforming device converts between different spatial audio formats (binaural, surround, stereo, mono) depending on the capabilities of the playback device, enabling the same content to adapt its spatial characteristics to match the output capabilities of various devices while preserving spatial information when appropriate
Solution Approach 2:
The patent changes audio parameters (channel configuration, spatial encoding) based on playback device characteristics. The system modifies spatial audio parameters such as channel count, inter-channel level differences, and inter-channel time differences to match the capabilities of the target playback device, resolving the contradiction between preserving spatial information and ensuring compatibility
2Measurement precision
If spatial audio content is optimized for immersive experiences, then audio quality is improved, but processing complexity deteriorates
Solution Approach 1:
The processing system is segmented into distinct functional modules: an analyzing device that characterizes playback devices, a transforming device that converts between formats, and a rendering device that generates final output. This segmentation allows complex spatial audio processing to be broken down into manageable, specialized components that can be optimized independently
Solution Approach 2:
The system introduces intermediate representations (such as binaural rendering from surround formats, or stereo downmix from surround formats) as bridging stages between the source spatial audio content and the final playback output. These intermediaries simplify the transformation process by providing standardized intermediate formats that can be easily converted to various output configurations
Data Source
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AI summary
There is inter alia disclosed an apparatus for spatial audio encoding configured to: determine, for two or more audio signals, a first spatial audio direction parameter and a second spatial audio direction parameter for providing spatial audio reproduction: quantize the first spatial audio direction parameter (301); transform the second spatial audio direction parameter to have an opposite spatial audio direction (303); determine a difference between the transformed second spatial audio direction parameter and the quantized first spatial audio direction parameter (305); and quantize the difference (307).