Multi-Channel Audio Encoding with Phase and Residual Signals

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Solution Overview

Problem

Existing multi-channel audio coding techniques, such as MPEG surround coding, fail to accurately decode original signals from parameter-encoded data, even with increased bit rates, due to insufficient information in the parameters used for down-mixed signals during up-mixing.

Innovation Solution

An encoding apparatus that extracts spatial parameters associated with phase information from multiple channel signals, down-mixes these signals, and encodes residual signals as error signals, allowing for hierarchical down-mixing and up-mixing processes to reproduce the original signals, using parameter encoders, down-mixing units, residual signal encoders, and up-mixing matrices based on estimated phase information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If parameter encoding is used to compress multi-channel signals, then bit rate is reduced, but decoding accuracy deteriorates

Engineering Contradiction:

Improvebit rateVSAvoiddecoding accuracy

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The multi-channel signal is segmented into down-mixed signals and residual signals. The down-mixed signals capture the main energy content while the residual signals capture the difference information. This segmentation allows efficient bit rate allocation where most bits are used for down-mixed signals and fewer bits for residual signals, achieving both compression and high decoding accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Down-mixed signals serve as an intermediary representation between the original multi-channel signals and the final decoded output. By encoding both the down-mixed signals and the residual signals, the system creates a intermediate representation that preserves essential spatial and temporal information while enabling efficient compression.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If hierarchical down-mixing is applied to compress multiple channels, then channel count is reduced, but signal fidelity deteriorates

Engineering Contradiction:

Improvechannel countVSAvoidsignal fidelity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The encoding process uses feedback by calculating residual signals as the difference between original multi-channel signals and reconstructed signals from down-mixed signals. This feedback mechanism allows the system to identify and encode the specific information lost during down-mixing, enabling accurate reconstruction of the original signals during decoding.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes parameters by encoding not only the down-mixed signals but also additional residual signal information. This parameter change allows the decoder to reconstruct the original multi-channel signals with high fidelity by combining the down-mixed signals with the residual correction information.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10163445B2Apparatus and method encoding/decoding with phase information and residual information

Publication Date: 2018.12.25 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided is an apparatus and method of encoding and decoding multiple channel signals based upon phase information and one or more residual signals.