Multichannel Audio Predictive Decoding With Parameter Error Recovery

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Solution Overview

Problem

Predictive coding schemes in stereo and multichannel audio encoding are sensitive to errors, leading to error propagation and inefficient bandwidth usage, especially in error-free channels.

Innovation Solution

A method and apparatus that replace decoded parameters with estimated parameters in a decoder when error propagation is detected, using a parameter stability measure and an activity detector to determine when to switch to estimated parameters, reducing bandwidth waste and preventing audio freezing during unstable scenes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If predictive coding schemes are used to reduce bandwidth consumption, then bandwidth efficiency is improved, but error propagation occurs and reliability deteriorates

Engineering Contradiction:

Improvebandwidth consumptionVSAvoiderror propagation

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent implements dynamic switching between predictive coding mode and non-predictive coding mode based on channel conditions. When errors are detected, the system transitions from predictive coding (which saves bandwidth but propagates errors) to non-predictive coding (which consumes more bandwidth but prevents error propagation), thereby adapting the coding strategy to current channel reliability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where the decoder monitors for errors in received frames and sends information back to control the coding mode. The use of previous frame bad frame indicators and parameter stability measures creates a feedback loop that adjusts predictive coding usage based on observed error conditions, resolving the contradiction by reducing predictive coding when errors are present

Inventive Principle:

Principle #23Feedback

2Reliability

If parameter recovery is activated to mitigate error propagation, then reliability is improved, but bandwidth efficiency deteriorates

Engineering Contradiction:

Improveerror recoveryVSAvoidbandwidth efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies parameter recovery selectively rather than universally. It uses parameter stability measures to determine whether parameters have changed significantly, and only activates non-predictive coding when instability is detected or errors occur. This localized application of parameter recovery minimizes bandwidth overhead while maintaining reliability where needed

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the coding parameters dynamically based on stability measures and error conditions. When parameters are stable, predictive coding with parameter differences is used for efficiency. When parameters become unstable or errors are detected, the system switches to transmitting absolute parameters, thereby adapting the parameter representation to current conditions and balancing reliability with bandwidth efficiency

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If predictive coding is used continuously, then bandwidth consumption is reduced, but audio quality deteriorates during error conditions

Engineering Contradiction:

Improvebandwidth consumptionVSAvoidaudio quality

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent dynamically adjusts coding precision based on channel conditions. During error-free periods, predictive coding maintains acceptable audio quality with lower bandwidth. When errors are detected, the system switches to non-predictive coding to restore audio quality by transmitting full parameter information, thereby maintaining quality where needed while saving bandwidth when possible

Inventive Principle:

Principle #15Dynamics

4Loss of energy

If parameter stability measure is used to control parameter recovery, then bandwidth efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoiddecoder complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent replaces complex error correction mechanisms with a simpler parameter stability monitoring approach. Instead of using elaborate forward error correction or redundant coding schemes, the system uses relatively simple stability measures (comparing parameter values across frames) to trigger selective parameter recovery, thereby achieving good bandwidth efficiency with moderate decoder complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12488802B2Method and apparatus for error recovery in predictive coding in multichannel audio frames

Publication Date: 2025.12.02 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method, apparatus and decoder for replacing decoded parameters in a received multichannel signal in which a frame of consecutive frames of the received multichannel signal is decoded and responsive to receiving a previous frame bad frame indicator while operating in a predictive decoding mode with a current frame of the consecutive frames, it is determined whether a parameter stability measure is below a threshold. Responsive to the parameter stability measure being below the threshold a parameter recovery is activated by retrieving the estimated parameters and replacing decoded parameters of the current frame with the estimated parameters. Otherwise, it is detected whether a source is an active source and responsive to the source being an active source, decoded parameters of the current frame are stored as estimated parameters and the parameter stability measure is determined.