Parametric Audio Decoding Stereo Parameter Conditioning

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Solution Overview

Problem

Existing audio decoding technologies face challenges in faithfully reproducing audio signals due to mismatches in encoder and decoder windowing schemes, leading to sound artifacts and reduced audio quality.

Innovation Solution

The implementation of a system that receives a bitstream containing encoded mid signals and stereo parameter information, performs decoding, transforms the signals using a decoder-side windowing scheme, conditions the stereo parameters, and applies these conditioned values during up-mixing to generate high-quality output signals, thereby reducing artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If encoder-side windowing scheme is used to determine stereo parameter values, then audio encoding efficiency is improved, but decoder-side audio fidelity deteriorates due to mismatch with decoder windowing scheme

Engineering Contradiction:

Improveaudio encoding efficiencyVSAvoidaudio decoding fidelity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent transforms stereo parameter values by applying the ratio of decoder window values to encoder window values. This parameter transformation aligns the encoder-determined stereo parameters with the decoder's windowing scheme, resolving the mismatch while preserving encoding efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary transformation process that converts stereo parameter values from encoder windowing domain to decoder windowing domain. This intermediary step acts as a bridge between the two different windowing schemes, enabling faithful reproduction without requiring both encoder and decoder to use the same windowing approach.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If stereo parameter values are directly applied from encoder to decoder, then device complexity is reduced, but audio quality deteriorates due to sound artifacts

Engineering Contradiction:

Improvedecoder structure complexityVSAvoidaudio sound artifacts

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent applies a mathematical transformation to stereo parameter values by multiplying them with the ratio of decoder window values to encoder window values. This parameter change eliminates sound artifacts caused by windowing mismatches while adding only a simple computational step to the decoder.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful effect of windowing scheme mismatches into a beneficial transformation process. By applying the window value ratio as a correction factor, the system turns the discrepancy between encoder and decoder windowing into a systematic correction mechanism that improves audio fidelity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12022274B2Parametric audio decoding

Publication Date: 2024.06.25 QUALCOMM INC

AI summary

An apparatus includes a receiver and an up-mixer. The receiver is configured to receive a bitstream that includes an encoded mid signal and encoded stereo parameter information. The encoded stereo parameter information represents a first value of a stereo parameter and a second value of the stereo parameter. The first value is associated with a first frequency range. The second value is associated with a second frequency range that is distinct from the first frequency range. The up-mixer is configured to perform an up-mix operation on a frequency-domain decoded mid signal generated from the encoded mid signal. A particular value based on the first value and the second value is applied to the frequency-domain decoded mid signal during the up-mix operation.