Social Media Video Synchronization via Audio Correlation

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Solution Overview

Problem

The challenge lies in synchronizing multiple video recordings from diverse sources without a universal time reference, particularly in social events where recordings have varying sound quality, camera resolution, and camera shake, making it difficult to align them on a single timeline for effective sharing and editing.

Innovation Solution

A method that matches pairs of audio signals to estimate candidate time offsets, assigns confidence measures based on audio features, and combines these offsets using a graphical representation and Belief Propagation algorithm to determine final time offsets for video recordings relative to a reference timeline.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple video recordings from diverse sources are synchronized without a universal time reference, then the ability to share and edit complete event recordings is enhanced, but the complexity of determining time offsets between recordings increases

Engineering Contradiction:
Improveability to share and edit complete event recordingsVSAvoidcomplexity of determining time offsets
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses audio signals as an intermediary to establish time relationships between video recordings. By extracting and comparing audio features (spectrograms, correlation functions) from different recordings, the system creates a reference framework that mediates the synchronization process, allowing time offsets to be determined without requiring universal time references from the original recording devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/hardware-based synchronization approach (genlocking, universal time references) with a signal-processing-based approach. By substituting the physical time reference mechanism with audio signal correlation and belief propagation algorithms, the system achieves synchronization through software-based temporal relationship inference.

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

2Adaptability or versatility

If audio signals with varying sound quality and local noise are used for synchronization, then more diverse video recordings can be synchronized, but the precision of time offset estimation deteriorates

Engineering Contradiction:
Improvenumber of diverse video recordings that can be synchronizedVSAvoidprecision of time offset estimation
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements feedback through the belief propagation algorithm, which iteratively refines time offset estimates by comparing audio signals across multiple recording pairs. The system continuously adjusts probability distributions of time offsets based on correlation measurements, allowing it to converge on accurate estimates even when individual audio signals contain noise or quality variations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent combines information from multiple audio signal comparisons to determine time offsets. By merging the results from many different recording pairs and using belief propagation to aggregate these measurements, the system achieves robust time offset estimation that compensates for the poor quality or noise in individual audio signals.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If a reference timeline is created using audio feature matching, then all video recordings can be aligned on a single timeline, but the computational resources required for matching and combining time offsets increase

Engineering Contradiction:
Improveefficiency of video alignment and editingVSAvoidcomputational resources for signal processing
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent segments the synchronization problem into manageable stages: extracting audio features from individual recordings, computing pairwise time offsets through correlation, and finally combining these offsets using belief propagation. This segmentation allows the system to process recordings in discrete steps rather than requiring simultaneous processing of all signals at once, reducing peak computational demands.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2896043B1Inter-stream audio/video synchronisation of social media
Publication Date: 2017.02.01 GOOGLE LLC
  • EP2896043B1 patent drawingFigure 1
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AI summary

Provided are methods for synchronizing multiple video recordings of the same event using audio signals of the recordings. An algorithm is designed to generate candidate time offsets for pairwise matches of video recordings based on audio signals corresponding to the recordings, and combine the candidate time offsets to obtain the most accurate actual time offset between each pair of recordings. Each candidate time offset for each pairwise match of recordings is assigned a confidence measure indicating how likely it is that the particular time offset is correct for the given pair of recordings. The confidence measure assigned to a particular time offset is based on various components and characteristics of the audio signal pair corresponding to the video recordings.