Audio Synchronization Unit for Distributed Media Playback

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Solution Overview

Problem

Existing video conferencing systems face challenges in synchronizing audio-visual content across multiple stations with different content sources, such as terrestrial broadcasts, satellite signals, DVDs, and over-the-top streaming, leading to timing differences and difficulties in maintaining synchronized playback.

Innovation Solution

A method and apparatus for synchronizing content playback across stations using audio feature extraction and pattern matching, where one station adjusts its playback by skipping backward or pausing to match the lead station's timing, ensuring synchronized audio and video playback through communication and feature detection modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different content sources are used at multiple stations (terrestrial broadcast, satellite signal, DVD, streaming), then content accessibility and versatility are improved, but synchronization accuracy deteriorates due to timing differences and varying delays

Engineering Contradiction:
Improvecontent source compatibilityVSAvoidsynchronization accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system uses microphones at each station to capture audio output from speakers, then compares the captured audio signals to detect timing differences. This feedback loop continuously monitors and measures synchronization status, enabling real-time detection of drift between stations playing from different content sources.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical synchronization methods (which assume identical content sources and timing) with acoustic field-based detection. By using microphones to capture and compare audio signals, the system creates a new detection mechanism that works across diverse content sources, substituting the old mechanical timing assumption with acoustic pattern matching.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Difficulty of detecting and measuring

If audio feedback and pattern matching are used to detect synchronization, then synchronization detection capability is improved, but device complexity increases due to additional microphones, signal processing, and pattern matching algorithms

Engineering Contradiction:
Improvesynchronization detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The system uses the existing audio output from each station's speakers and the built-in microphones to detect synchronization. Rather than requiring external synchronization equipment or complex centralized control, each station independently captures its own audio output and compares it with received audio signals from other stations, making the system self-sufficient and reducing overall complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The microphones and audio processing components serve multiple functions: they capture audio for synchronization detection, detect timing drift, and enable pattern matching across different content sources. This multi-functionality reduces the need for dedicated synchronization hardware, thereby limiting the increase in device complexity while maintaining high detection capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Effectively synchronizes audio and video content across stations with different content sources, ensuring that all participants experience the same media program simultaneously, even with varying delays and content start times.

Implementation Method 1

A microphone in the synchronization unit detects the audio from the speaker

Methodology Applied
Scientific EffectAcoustic detection: Sound

Implementation Method 2

The feature detection module extracts audio features from the captured audio

Methodology Applied
Scientific EffectAudio feature extraction: Sound

Implementation Method 3

The synchronization unit compares the audio features using pattern matching

Methodology Applied
Scientific EffectPattern matching:

Data Source

PatentEP3011691B1System and method to assist synchronization of distributed play out of control
Publication Date: 2022.11.30 INTERDIGITAL CE PATENT HOLDINGS SAS
  • EP3011691B1 patent drawingFigure 1
  • EP3011691B1 patent drawingFigure 2
  • EP3011691B1 patent drawingFigure 3

AI summary

A method for synchronizing content undergoing play out at first and second stations commences by comparing audio within content undergoing play out on the first station to the audio within content undergoing play out on the second station to determine if a latency exists between the first and second stations. If such a latency exists, then at least one of a pause or jump operations is performed in connection with content playing out by at least one of the first and second stations for an interval corresponding to an interval by which one station leads the other station to bring the two stations into substantial synchronism