Mismatched Windowing Audio Decoder Delay Reduction

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Solution Overview

Problem

Multichannel audio coding systems face delays due to mismatched windowing schemes used by encoders and decoders, which affect decoding efficiency and increase computational complexity.

Innovation Solution

Implementing mismatched windowing schemes between encoders and decoders, where the decoder uses windows with shorter overlapping portions and different characteristics compared to the encoder, to reduce decoding delay and computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If mismatched windowing schemes are used between encoder and decoder, then coding delay is reduced, but signal quality may deteriorate

Engineering Contradiction:
Improvecoding delayVSAvoidsignal quality
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

The patent changes the windowing parameters between encoder and decoder specifically - the encoder uses one set of windowing parameters while the decoder uses different windowing parameters. This parameter change allows the decoder to process signals with shorter overlapping portions, reducing coding delay while the mismatched scheme is designed to maintain signal quality through careful parameter selection.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If mismatched windowing schemes are used between encoder and decoder, then computational complexity is reduced, but decoding efficiency may worsen

Engineering Contradiction:
Improvecomputational complexityVSAvoiddecoding efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies parameter changes by using different windowing schemes with varying overlapping portion lengths. The decoder uses a windowing scheme with shorter overlapping portions compared to the encoder, which reduces the computational complexity of the decoding process while maintaining acceptable decoding efficiency through optimized parameter selection.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If shorter overlapping portions are used in decoder windows, then coding delay is reduced, but audio signal alignment may deteriorate

Engineering Contradiction:
Improvecoding delayVSAvoidaudio signal alignment
Core Design Contradiction:
Loss of timeVSStability of the object's composition

Solution Approach 1:

The patent introduces asymmetry in the windowing schemes between encoder and decoder. The encoder uses a windowing scheme with longer overlapping portions while the decoder uses a windowing scheme with shorter overlapping portions. This asymmetric approach allows the decoder to reduce coding delay while the careful design of the asymmetric scheme maintains audio signal alignment through compensated parameter relationships.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3430623B1Multi channel coding
Publication Date: 2020.01.01 QUALCOMM INC
  • EP3430623B1 patent drawingFigure 1
  • EP3430623B1 patent drawingFigure 2
  • EP3430623B1 patent drawingFigure 3

AI summary

A device includes a receiver and a decoder. The receiver is configured to receive stereo parameters encoded, by an encoder, based on a plurality of windows having a first length of overlapping portions between the plurality of windows. The decoder is configured to perform an upmix operation using the stereo parameters to generate at least two audio signals. The at least two audio signals are generated based on a second plurality of windows used in the upmix operation. The second plurality of windows has a second length of overlapping portions between the second plurality of windows. The second length is different from the first length.