Stereo-Channel Audio Coding With Integrated Surround Mapping
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Solution Overview
Problem
Current multi-channel audio coding systems are inefficient for mobile devices due to high bit rates and complexity, making it difficult to deliver multi-channel surround effects without additional processing resources, especially in portable devices.
Innovation Solution
A system that uses a smart surround mapping unit to integrate binaural and spatial information into stereo-channel audio signals, allowing for efficient encoding and decoding without the need for additional processing units, utilizing a nonlinear mapping scheme and pre-determined connection weights for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If spatial audio coding method is used to deliver low bit rate multi-channel signals, then bit rate is reduced, but computational complexity increases due to surround synthesis processing and virtual surround mapping
Solution Approach 1:
The patent extracts and transmits only the essential side information (ICTD, ICLD, ICC) needed for spatial audio reconstruction, separating this compact metadata from the full multi-channel signal processing. This allows the main audio signal to be transmitted at low bit rate while the computational complexity of generating full surround effects is avoided in portable devices.
Solution Approach 2:
The patent implements partial surround processing by providing only the most salient spatial cues (inter-channel time difference, level difference, and coherence) rather than complete multi-channel signal processing. This partial action delivers sufficient spatial effect for portable devices without requiring full computational complexity of virtual surround mapping units.
2Reliability
If surround synthesis processing unit and virtual surround mapping unit are implemented in portable devices, then multi-channel surround effect is achieved, but processing resources and cost increase
Solution Approach 1:
The patent enables existing stereo-channel decoders to serve dual purposes by designing the encoding system so that the same decoder can handle both regular stereo audio and spatially-encoded audio. The decoder uses its existing capabilities to process the transmitted side information and generate spatial effects without requiring additional dedicated processing units, thereby achieving surround effect quality while avoiding increased processing resources.
3Reliability
If multi-channel coding systems are used, then audio quality is improved, but bit rate and system complexity increase significantly
Solution Approach 1:
The patent segments the audio signal into a main stereo signal component and a separate side information component containing spatial parameters. This segmentation allows the main audio content to be transmitted efficiently while the segmented spatial parameters (ICTD, ICLD, ICC) are transmitted at minimal bit rate, achieving multi-channel audio quality without the high bit rate of traditional multi-channel coding systems.
Data Source
AI summary
A system for generating stereo-channel audio signals with surround information is disclosed. The system includes a surround mapping unit configured to receive signals from a number of audio channels and generate a pair of stereo-channel audio signals based on the audio channels. The pair of stereo-channel audio signals includes binaural and spatial information. The system also includes a stereo-channel encoder configured to receive and encode the pair of stereo-channel audio signals from the surround mapping unit thereby generating a pair of encoded stereo-channel audio signals. The system further includes a stereo-channel decoder configured to receive and decode the pair of encoded stereo-channel audio signals thereby obtaining the pair of stereo-channel audio signals. The pair of stereo-channel audio signals are capable of being used to generate surround effect.