Audio Video Synchronization Using Periodic Timing Signals
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Solution Overview
Problem
Current methods for synchronizing audio and video in media programs are complex, bandwidth-intensive, and not compatible across all formats, making it difficult to accurately measure and correct for synchronization errors without adding additional bandwidth or degrading the signal.
Innovation Solution
A method and apparatus that identify naturally occurring timing points in video signals and mark their relationship to audio signals using a timing signal, allowing for synchronization correction without additional bandwidth, using a video analysis module, timing signal generator, mixer, and synchronization detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If watermarking is used to carry audio signal in video signal for timing measurements, then synchronization measurement is achieved, but signal to noise ratio deteriorates and bandwidth is wasted
Solution Approach 1:
The patent introduces a separate timing measurement channel that carries timing information independently from the main audio and video signals. This intermediary channel uses dedicated bandwidth rather than embedding timing data in the video watermark, thus preserving the video signal quality and avoiding SNR deterioration while still achieving precise synchronization measurement.
2Reliability
If continuous audio signal is added for timing purposes, then timing signal is maintained, but additional bandwidth is required and original audio signal is compromised
Solution Approach 1:
The patent uses periodic test tones inserted at regular intervals (e.g., every few seconds) rather than continuous audio signals for timing measurement. This periodic approach maintains reliable timing information while significantly reducing the bandwidth consumption compared to continuous signal insertion, and allows the original audio content to remain uncompromised between test tone insertions.
3Quantity of substance
If attenuation of marking signal is used below audio portion, then bandwidth is saved, but precise synchronization cannot be achieved
Solution Approach 1:
The patent applies different signal qualities to different purposes: full-strength periodic test tones are used specifically for timing measurement moments to ensure precision, while the main audio signal maintains its original quality for content delivery. This local differentiation allows precise synchronization measurement at critical moments without permanently compromising bandwidth or audio quality throughout the entire signal stream.
4Reliability
If multiple elements are added to both video and audio signals for synchronization, then timing information is provided, but bandwidth is wasted and complexity increases
Solution Approach 1:
The patent extracts the timing measurement function from the main audio and video signal paths and places it in a separate dedicated timing measurement channel. This separation removes the complexity of managing multiple synchronized elements across different signal paths and eliminates the bandwidth waste of adding redundant timing information to both audio and video, while maintaining reliable timing information through the dedicated channel.
Data Source
AI summary
A method and apparatus for synchronizing audio and video portions of a media program signal is disclosed. In a transmitting embodiment, the method comprises the steps of identifying a video event according to an video event discriminant in the video signal, and inserting a timing signal into the audio signal, and the apparatus comprises a video analysis module for identifying a video event according to an video event discriminant in the video signal, a timing signal generator for generating a timing signal, and a mixer for inserting the timing signal into the audio signal.