Spatial Audio Latency Reduction via Single-Channel Difference Signal
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Solution Overview
Problem
Existing spatial audio solutions experience delays in rendering audio source directions when a user changes their point of view, resulting in lagged sound source positioning due to the transmission and processing of point of view data and audio signals.
Innovation Solution
An apparatus and method that determine a single-channel difference audio signal based on the difference between audio signals for different points of view, allowing for the estimation of both channels of the audio signal at the new point of view, reducing the need to transmit multiple audio signals and minimizing latency by using a single-channel difference signal for adaptive playback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transmitter apparatus transmits full audio signals for multiple points of view, then the audio quality is maintained, but the bit rate and processing complexity increase significantly
Solution Approach 1:
The patent extracts only the essential information needed for spatial audio adaptation by transmitting a single-channel difference signal that represents the difference between audio channels, rather than transmitting complete multi-channel audio signals for multiple points of view. This extraction approach maintains audio quality while significantly reducing bit rate.
Solution Approach 2:
The patent creates a simplified copy of the audio information in the form of a difference signal that can be reused for symmetric points of view. Instead of transmitting separate audio signals for each viewpoint, a single difference signal is transmitted and then copied/adapted for multiple symmetric viewpoints, reducing the overall data transmission requirement.
2Measurement precision
If the transmitter apparatus processes and transmits audio signals in real-time, then the audio rendering is accurate, but the latency increases due to multiple processing steps
Solution Approach 1:
The patent performs preliminary processing to create a single-channel difference signal that encapsulates the essential spatial audio information. This preliminary action allows the receiver to reconstruct audio for multiple points of view with minimal additional processing, thereby reducing overall latency while maintaining rendering accuracy.
3Measurement precision
If the system transmits separate difference signals for each point of view, then the spatial audio accuracy is improved, but the bit rate increases
Solution Approach 1:
The patent makes the single-channel difference signal universal by designing it to be reusable for multiple symmetric points of view. This single difference signal serves multiple functions, enabling the reconstruction of audio for different spatial positions without requiring separate difference signals for each viewpoint, thus maintaining spatial audio accuracy while minimizing bit rate.
4Productivity
If the receiver apparatus decodes and processes low-bitrate coded audio, then the transmission efficiency is improved, but the processing complexity and potential quality loss increase
Solution Approach 1:
The single-channel difference signal acts as an intermediary that bridges the transmitter and receiver efficiently. This intermediary signal format enables compact representation that is easy to transmit and decode, while the receiver uses this difference signal to reconstruct the full spatial audio experience, balancing transmission efficiency with processing simplicity.
Data Source
AI summary
An apparatus, for enabling adaptive playback, comprising means configured to: obtain, for a first point of view, a first audio signal for at least a first channel and a second channel; obtain, for a second point of view, a second audio signal for at least the first channel and the second channel; determine a single-channel difference audio signal, for the second point of view, based on at least a difference between the first audio signal and the second audio signal; and enable estimation of both the first channel and the second channel of the second audio signal for the second point of view in dependence on the single-channel difference audio signal and the first audio signal.