SAOC Un-Mixing With Dual-Resolution Side Information

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Solution Overview

Problem

Current audio object coding schemes, such as MPEG SAOC, suffer from limited frequency resolution, leading to audible artifacts like 'halo' effects around tonal sounds, and increasing resolution to improve separation quality results in impractically high side information rates, compromising compatibility with existing systems.

Innovation Solution

An enhanced SAOC system that dynamically adjusts time-frequency resolution for audio object coding, allowing for higher frequency selectivity and temporal precision, while maintaining backward compatibility through a compact parameterization that can be decoded by both standard and enhanced decoders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the frequency resolution of parametric side information is increased to improve audio object separation quality, then the separation quality improves, but the side information rate becomes impractically high

Engineering Contradiction:
Improvefrequency resolutionVSAvoidside information rate
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the side information into two distinct parts: a first parametric side information at a first frequency resolution, and a second parametric side information at a second frequency resolution. This segmentation allows the system to deliver both coarse and fine frequency resolution information without requiring the entire side information to be at high resolution, thus reducing the overall side information rate while maintaining separation quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by providing different frequency resolutions for different aspects of the audio signal processing. The first parametric side information provides sufficient resolution for basic separation, while the second parametric side information provides enhanced resolution only where needed for specific audio objects or frequency regions, optimizing the trade-off between quality and data rate.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the frequency resolution of parametric side information is increased to reduce audible artifacts, then the perceptual quality improves, but the compatibility with existing systems deteriorates

Engineering Contradiction:
Improvefrequency resolutionVSAvoidsystem compatibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal side information structure that serves multiple functions and decoder types. The first parametric side information at the first frequency resolution ensures compatibility with existing SAOC decoders, while the second parametric side information at the second frequency resolution enables enhanced quality for advanced decoders. This multi-functional approach allows the same encoded audio signal to be decoded by both standard and enhanced decoders without loss of compatibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements a dynamic side information delivery system where the decoder can adaptively use the available parametric side information based on its capabilities. Enhanced decoders can utilize both first and second parametric side information when available, while standard decoders rely on the first parametric side information, allowing the system to dynamically adjust to different decoder types and maintain compatibility across the ecosystem.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the time-frequency resolution is dynamically adjusted for different audio objects, then the separation quality improves, but the processing complexity increases

Engineering Contradiction:
Improvetime-frequency resolutionVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameters of the parametric side information by providing two different frequency resolutions. This parameter change allows the system to adapt the time-frequency resolution to the specific requirements of different audio objects without fundamentally changing the processing architecture, thereby improving separation quality while controlling processing complexity through parameter variation rather than structural complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2904609B1Encoder, decoder and methods for backward compatible multi-resolution spatial-audio-object-coding
Publication Date: 2018.10.31 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2904609B1 patent drawingFigure 1A
  • EP2904609B1 patent drawingFigure 1B
  • EP2904609B1 patent drawingFigure 2A

AI summary

A decoder for generating an un-mixed audio signal comprising a plurality of un-mixed audio Channels is provided. Moreover, an encoder and an encoded audio signal is provided. The decoder comprises an un-mixing-information determiner for determining un-mixing information by receiving first parametric side information on the at least one audio object signal and second parametric side information on the at least one audio object signal, wherein the frequency resolution of the second parametric side information is higher than the frequency resolution of the first parametric side information. Moreover, the decoder comprises an un-mix module for applying the un-mixing information on a downmix signal, indicating a downmix of at least one audio object signal, to obtain an un-mixed audio signal comprising the plurality of un-mixed audio Channels. The un-mixing-information determiner is configured to determine the un-mixing information by modifying the first parametric information and the second parametric information to obtain modified parametric information, such that the modified parametric information has a frequency resolution which is higher than the first frequency resolution.