Multi-Channel Audio Upmixing With Section-Based Ambience Segmentation
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Solution Overview
Problem
Existing multi-channel audio upmix methods, particularly blind upmix, struggle to generate immersive ambience without artifacts, especially for signals like applause and rain, which require precise spatial and temporal distribution of sound components, often resulting in distorted or limited sound impressions.
Innovation Solution
An apparatus and method that includes a main signal upmixing component, a section selector, and a combiner to analyze and enhance the input audio signal by selecting and upmixing specific sections, allowing for flexible distribution of sound particles across multiple channels, thereby improving sound quality and immersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blind upmix methods are used to generate multi-channel signals without additional data, then the complete available reproduction system can be utilized, but the sound impression becomes limited and artifacts occur
Solution Approach 1:
The input audio signal is divided into direct sound sources and ambience portions using signal analysis. Direct sound sources are reproduced by front channels while ambience portions are distributed to surround channels, allowing each channel type to handle appropriate signal components separately and improve overall sound quality
Solution Approach 2:
The system changes signal processing parameters by applying different handling to direct sound sources versus ambience portions. Direct sounds maintain their original characteristics while ambience signals are decorrelated and distributed, optimizing the reproduction for each signal type
2Ease of operation
If decorrelation methods are applied to distribute sound components, then enveloping effect is achieved, but transient structures lose their transient character and artifacts occur
Solution Approach 1:
Different processing qualities are applied to different signal components: direct sound sources are reproduced with high fidelity to preserve transient character, while ambience portions receive decorrelation processing to create enveloping effect, with each component treated according to its specific requirements
3Ease of operation
If direct ambience concept is used to reproduce ambience portions in surround channels, then enveloping ambience is achieved, but immersive ambience with direct sound character is lost
Solution Approach 1:
The system segments ambience signals into individual sound particles that can be independently positioned and distributed. This allows ambience to be reproduced as discrete directional sounds rather than diffuse ambient noise, creating immersive spatial perception while maintaining enveloping effect
Solution Approach 2:
The system adds spatial dimensionality to ambience reproduction by distributing sound particles across multiple surround channels with specific positioning. This transforms flat ambience into three-dimensional spatial audio, enabling immersive experience while preserving enveloping characteristics
Data Source
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AI summary
An apparatus (100) for generating a multi-channel audio signal (142) based on an input audio signal (102) comprises a main signal upmixing means (110), a section selector (120), a section signal upmixing means (110) and a combiner (140). The main signal upmixing means (110) is configured to provide a main multi-channel audio signal (112) based on the input audio signal (102). The section selector (120) is configured to select or not select a section of the input audio signal (102) based on an analysis of the input audio signal (102). The selected section of the input audio signal (102), a processed selected section of the input audio signal (102) or a reference signal associated with the selected section of the input audio signal (102) is provided as section signal (122). The section signal upmixing means (130) is configured to provide a section upmix signal (132) based on the section signal (122), and the combiner (140) is configured to overlay the main multi-channel audio signal (112) and the section upmix signal (132) to obtain the multi-channel audio signal (142).