Audio-Video Sync Detection Using Anchor Frames and Audio Cues

Solution Overview

Problem

Audio and video signals in multimedia content often experience synchronization issues during recording and transmission due to unpredictable delays in processing and network transmission, leading to audio lagging behind or ahead of video, which can be challenging to correct.

Innovation Solution

A system and method for detecting audio/video synchronization errors by identifying anchor frames coinciding with moments of silence or high audio levels, using a content analyzer to verify temporal alignment and correct synchronization errors through delay compensation based on content type and drift thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If audio and video signals are transmitted over a network, then multimedia content can be delivered to users, but synchronization errors occur due to unpredictable delays in processing and transmission

Engineering Contradiction:

Improvemultimedia content deliveryVSAvoidaudio-video synchronization

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary analysis of video frames to identify anchor frames (I-frames) before audio synchronization can be established. By pre-identifying these reference frames and their timestamps, the system prepares the necessary data structures and metadata in advance, enabling faster and more accurate audio-video sync establishment when the media content is played back, thus resolving the synchronization issue without compromising delivery speed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where audio timestamps are continuously compared with video anchor frame timestamps to detect drift. When synchronization errors are detected, the system adjusts audio playback timing based on the calculated drift, creating a closed-loop control system that maintains synchronization despite network delays and processing variations

Inventive Principle:

Principle #23Feedback

2Speed

If processing delays are reduced to improve real-time performance, then transmission speed increases, but synchronization accuracy deteriorates due to unpredictable delays

Engineering Contradiction:

Improvesignal processing speedVSAvoidsynchronization accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The system performs preliminary analysis of video frames to identify anchor frames (I-frames) before audio synchronization can be established. By pre-identifying these reference frames and their timestamps, the system prepares the necessary data structures and metadata in advance, enabling faster and more accurate audio-video sync establishment when the media content is played back, thus resolving the synchronization issue without compromising delivery speed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where audio timestamps are continuously compared with video anchor frame timestamps to detect drift. When synchronization errors are detected, the system adjusts audio playback timing based on the calculated drift, creating a closed-loop control system that maintains synchronization despite network delays and processing variations

Inventive Principle:

Principle #23Feedback

3Reliability

If anchor frames are used to detect scene changes, then synchronization errors can be identified, but false positives occur when anchor frames coincide with silence or high audio levels

Engineering Contradiction:

Improvescene change detectionVSAvoidsynchronization error detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system introduces an intermediary verification step using audio level analysis. Instead of directly equating anchor frames with scene changes, the system uses audio silence detection as a mediator to verify whether an anchor frame truly indicates a scene change. This intermediary check filters out false positives where anchor frames coincidentally align with silence or high audio levels, improving detection accuracy without reducing reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces the mechanical assumption that anchor frames always indicate scene changes with a more sophisticated verification mechanism. Instead of directly using anchor frame detection, the system substitutes this with an audio-based verification process that analyzes audio levels and silence patterns, replacing the simple mechanical detection with a more nuanced verification system that reduces false positives

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20250373879A1Audio Video Synchronization

Publication Date: 2025.12.04 COMCAST CABLE COMM LLC

AI summary

Systems, methods, and apparatuses are described for detecting synchronization errors between audio and video signals. Scene changes may be detected based on anchor frames. Offsets between a scene change in a video signal and a reduced audio level or burst of high audio level in the audio signal may indicate a synchronization error.