Deep Learning Audio Packet Loss Concealment

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Solution Overview

Problem

Existing packet loss concealment techniques in audio processing, such as those used in VoIP and audio streaming, are inadequate in providing a smooth listening experience due to packet loss and delay over asynchronous networks like IP networks, as they often rely on receiver-based methods that are not effective in real-time scenarios.

Innovation Solution

Implementing machine learning models, specifically deep learning, to infer and recover lost audio frames by splitting previous frames into high-band and low-band signals, inferring the low-band signal, and combining it with the high-band signal to reconstruct the frame, while also adding noise and smoothing the frame in the time or frequency domain to enhance voice quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional receiver-based packet loss concealment techniques are used, then implementation simplicity is maintained, but voice quality and listening experience deteriorate due to inadequate compensation for packet loss and delay

Engineering Contradiction:
Improvevoice qualityVSAvoidconcealment technique complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the audio signal processing into distinct frequency bands (low-band and high-band). The machine learning model specifically infers only the low-band signal components, while the high-band components are handled separately through traditional interpolation or copying methods. This segmentation allows the complex ML approach to focus on the most critical frequency range, improving voice quality without requiring the entire signal processing chain to be overly complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary splitting of the audio signal into frequency bands before the inference process. By pre-processing the signal to separate low-band and high-band components, the system prepares the data in an optimal format for the machine learning model to work with, reducing the computational burden during real-time packet loss concealment and improving overall processing efficiency.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If complex machine learning models are applied to infer lost frames, then voice quality improves, but computation complexity and time delay increase

Engineering Contradiction:
Improvepacket loss mitigationVSAvoidcomputation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the audio spectrum into low-band and high-band segments, applying the computationally intensive machine learning inference only to the low-band portion. This segmentation strategy reduces the dimensionality of the problem the ML model must solve, thereby lowering computation complexity while still achieving significant packet loss mitigation through accurate low-band reconstruction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies machine learning inference selectively only to the low-band signal components rather than processing the entire audio spectrum. This partial action approach focuses computational resources on the frequency range that contributes most to voice quality, achieving effective packet loss mitigation without the excessive computation that would result from processing all frequency bands with ML.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If machine learning inference is performed for lost frame recovery, then listening experience improves, but time delay increases due to processing requirements

Engineering Contradiction:
Improveaudio stream recoveryVSAvoidtime delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the audio processing task to apply ML inference only to low-band components, which reduces the amount of computation required compared to full-band processing. This segmentation enables faster inference times, thereby reducing the time delay introduced by packet loss concealment while still achieving effective audio stream recovery.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs partial inference by focusing machine learning processing only on the low-band signal portion rather than the complete audio signal. This partial processing approach significantly reduces the computational load and inference time, minimizing time delay while maintaining effective audio recovery quality.

Inventive Principle:
Principle #16Partial or excessive action

4Productivity

If simple frame copying or interpolation is used, then computation time is reduced, but voice quality and smoothness deteriorate

Engineering Contradiction:
Improveprocessing speedVSAvoidaudio quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the audio signal into low-band and high-band components, applying machine learning inference specifically to the low-band portion to improve voice quality. Meanwhile, the high-band components are reconstructed using simpler and faster methods such as copying or interpolation, thereby maintaining acceptable processing speed while achieving superior overall audio quality compared to uniform simple processing.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11646042B2Digital voice packet loss concealment using deep learning
Publication Date: 2023.05.09 AGORA LAB INC
  • US11646042B2 patent drawing
  • US11646042B2 patent drawing
  • US11646042B2 patent drawing

AI summary

A method for recovering a current frame of an audio stream includes detecting that a current packet is lost, the current packet including an audio signal; splitting one or more frames into respective high-band signals and respective low-band signals, the one or more frames precede the current frame in the audio stream; inferring a current low-band signal of the current frame using, as inputs to a machine-learning model, the respective low-band signals; combining the inferred current low-band signal with the respective high-band signals to obtain the current frame; and adding the current frame to a playout buffer.