Smart Audio Coding Mode Switching for Packet Loss Mitigation

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Solution Overview

Problem

Existing voice communication technologies face challenges in maintaining high-quality audio transmission due to packet loss and network conditions, leading to increased end-to-end delay and reduced user experience, as conventional FEC schemes either introduce additional delay or compromise baseline speech quality.

Innovation Solution

A device and method that dynamically adjust the coding mode by switching between primary frame encoding with and without redundant frame encoding, based on network conditions and real-time quality metrics, using a de-jitter buffer and analyzer to determine when to request a coding mode change from a channel-aware mode to a non-channel-aware mode, thereby optimizing speech quality, delay, and data rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the buffer depth of the de-jitter buffer is increased, then the quality of the processed audio signal improves, but the end-to-end delay increases

Engineering Contradiction:
Improvequality of processed audio signalVSAvoidend-to-end delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic buffer depth adjustment where the de-jitter buffer adapts its depth based on real-time network conditions. When network conditions are good, the buffer depth is reduced to minimize delay. When packet loss increases, the buffer depth is increased to allow more packets to be collected for error recovery, thus dynamically optimizing the trade-off between quality and delay.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the buffer depth parameter adaptively based on channel conditions. The analyzer monitors network conditions and triggers buffer depth adjustments when specific conditions are met, allowing the system to optimize audio quality by collecting more packets when needed while maintaining low latency when possible.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If the buffer depth of the de-jitter buffer is reduced, then the end-to-end delay decreases, but the quality of the processed audio signal deteriorates

Engineering Contradiction:
Improveend-to-end delayVSAvoidquality of processed audio signal
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The buffer operates dynamically with adjustable depth rather than a fixed value. This allows the system to reduce buffer depth to minimize delay when network conditions permit, while having the capability to increase depth when quality requirements demand it, based on real-time analyzer feedback.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The buffer depth parameter is changed adaptively based on channel conditions. When the analyzer determines that network conditions are favorable, the buffer depth is reduced to achieve lower latency. When conditions deteriorate, the parameter is adjusted upward to maintain audio quality.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If redundant frame encoding is used, then speech quality under packet loss improves, but data rate increases

Engineering Contradiction:
Improvespeech quality under packet lossVSAvoiddata rate
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of always transmitting full redundant frames, the system uses partial frame encoding where only essential portions of frames are transmitted as redundancy. This provides error recovery capability while using fewer bits than complete redundant frame transmission, thus improving speech quality under packet loss with a more moderate increase in data rate.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The coding mode parameter is changed dynamically between different encoding schemes. The system can switch between modes with and without redundant frame encoding based on network conditions, allowing optimization of the trade-off between speech quality reliability and data rate consumption.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If coding mode is changed dynamically, then optimization of speech quality and delay is achieved, but system complexity increases

Engineering Contradiction:
Improvespeech qualityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements a feedback mechanism where the analyzer monitors network conditions and provides information to trigger coding mode changes. This feedback loop allows the system to automatically adapt to changing conditions and optimize speech quality without requiring complex manual control or intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The de-jitter buffer and analyzer work together in a self-service manner where the analyzer automatically detects when coding mode changes are needed based on predefined conditions, and the buffer self-adjusts its operation mode without external intervention, reducing the complexity of external control systems.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS20190371345A1Smart coding mode switching in audio rate adaptation
Publication Date: 2019.12.05 QUALCOMM INC
  • US20190371345A1 patent drawing
  • US20190371345A1 patent drawing
  • US20190371345A1 patent drawing

AI summary

A method of smart coding mode switching includes receiving a first data including a primary copy and a partial copy. The method includes determining if switching a coding mode from channel aware mode to non-channel aware mode may be advantageous. The method further includes transmitting a request to another device for coding mode switch in response to determination result. The method includes receiving and decoding of a second data that includes a primary copy.