Audio Signal Encoding with Adaptive Enhancement Sample Selection

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Solution Overview

Problem

Existing speech/audio encoding and decoding methods face challenges in enhancing the quality of the core layer without sufficient bits, particularly in wideband and ultra-wideband signal processing, where traditional methods either require excessive bits or have limited application scope.

Innovation Solution

A method that selects and encodes enhancement sample points based on the available bits for the enhancement layer, improving core layer quality by adaptively adjusting enhancement sample points, even when bits are limited, using techniques like sub-band processing and residual symbol encoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If scalar or vector quantized bits are added to improve core layer encoding precision, then core layer quality is enhanced, but a large number of extra bits are required which increases the burden of the extended codec

Engineering Contradiction:
Improvecore layer encoding precisionVSAvoidnumber of extra bits
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent segments the enhancement layer encoding into two parts: core layer signal (encoded with traditional PCM) and difference signal (encoded with improved precision quantization). Only the difference signal receives enhanced quantization precision, while the core layer maintains its original encoding. This segmentation allows precision enhancement without uniformly increasing bit consumption across the entire signal, thereby resolving the contradiction between core layer quality and bit consumption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality enhancement by focusing computational resources and quantization precision specifically on the difference signal between enhancement layer and core layer, rather than uniformly enhancing the entire signal. This localized approach improves core layer quality where it matters most (in the residual error) while minimizing overall bit consumption, directly addressing the technical contradiction.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If pre-processing or post-processing technology is used to enhance core layer quality, then no extra bits are required, but the application scope is limited and enhancement effect is insufficient for most traditional codecs

Engineering Contradiction:
Improvenumber of extra bitsVSAvoidapplication scope and enhancement effect
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adaptability by allowing the system to operate in multiple modes: it can function as a traditional PCM codec when enhancement is not needed, or switch to an enhanced mode when improvement is required. The enhancement mechanism dynamically adjusts based on the specific codec and application requirements, making it versatile across different traditional codecs while maintaining broad adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary difference signal encoding mechanism that bridges between the core layer and the enhanced output. This intermediary layer uses improved quantization precision specifically for the residual signal, acting as a mediator that enhances quality without requiring complete redesign of the traditional codec architecture, thus expanding application scope while maintaining compatibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If each sample point is enhanced by consuming 2 bits in PCM-based scalar quantizer, then core layer quality is improved, but the burden of the extended codec increases greatly and sufficient bits are not available in many cases

Engineering Contradiction:
Improvecore layer encoding precisionVSAvoidburden of extended codec
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by enhancing only the difference signal rather than every sample point in the enhancement layer. This selective enhancement provides sufficient quality improvement for core layer reconstruction without the excessive bit consumption of uniformly enhancing all sample points, thereby reducing extended codec burden while maintaining adequate precision.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the quantization precision parameter selectively - using higher precision for the difference signal and standard precision for the core layer signal. This parameter differentiation allows the system to achieve necessary enhancement precision only where required, reducing overall bit consumption and extending codec burden while maintaining core layer quality.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2352230B8Signal encoding method and signal encoding device for a speech or audio signal
Publication Date: 2017.09.13 HUAWEI TECH CO LTD

AI summary

A method, device and system for signal encoding and decoding are disclosed. The method includes: encoding a core layer signal to obtain a core layer signal code; selecting an enhancement sample point that requires enhancement layer signal encoding according to the core layer signal code and the number of bits that can be used by an enhancement layer; obtaining an enhancement layer signal code of the enhancement sample point; and outputting a bit stream, where the bit stream includes the core layer signal code and the enhancement layer signal code. In embodiments of the present invention, according to the number of bits that can be used by the enhancement layer, the enhancement sample point that requires enhancement layer signal encoding is selected; the enhancement layer signal of the selected enhancement sample point is encoded and decoded; when no sufficient bits are available for the enhancement layer, the enhancement quality of the core layer can be improved.