Automatic IP Video Signal Timing Correction
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Solution Overview
Problem
In media production studios, aligning video signals from source devices to a system reference point device over an IP network is time and labor intensive, as traditional methods do not account for transmission latency, leading to timing errors and misalignment of signals.
Innovation Solution
A method that generates timestamps at both the system reference point device and source devices to determine transmission delays, allowing for the calculation of a video transmission correction factor, which is used to adjust the timing of video signal transmission from source devices to ensure alignment with other signals at the system reference point device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual timing adjustment is used, then signal alignment can be achieved, but time and labor consumption increases significantly
Solution Approach 1:
The system performs self-timing adjustment by automatically measuring transmission delays and calculating correction factors without requiring technician intervention. Each source device autonomously exchanges timestamps with the reference device, determines its own delay characteristics, and applies the appropriate timing correction, eliminating manual labor while maintaining alignment precision.
Solution Approach 2:
The system implements a feedback mechanism where timestamp exchanges provide information about actual transmission delays. This feedback is used to calculate correction factors that are applied to future transmissions, enabling automatic closed-loop timing adjustment that continuously maintains signal alignment without manual intervention.
2Device complexity
If traditional direct connection is used, then signal transmission is simple, but transmission delay variations cause timing misalignment
Solution Approach 1:
Timestamps serve as an intermediary mechanism that indirectly measures transmission delay characteristics. Instead of directly controlling signal timing, the system uses timestamp exchanges as a mediator to gather information about network conditions, which then informs the calculation of correction factors applied to actual video signal transmissions.
3Productivity
If automatic timing adjustment is implemented, then labor requirements decrease, but system complexity increases due to timestamp exchange protocols
Solution Approach 1:
The timestamp exchange protocol serves multiple functions simultaneously: it measures transmission delay, synchronizes clocks between devices, and provides data for correction factor calculation. This multi-functionality reduces the need for separate dedicated timing measurement systems, thereby limiting the increase in overall system complexity while achieving automatic timing adjustment.
Data Source
AI summary
Embodiments herein describe automatically synchronizing the output of source devices connected to a system reference point through an IP network in a media production studio so that the outputs are aligned when they reach the system reference point. In one embodiment, the system reference point device exchanges a plurality of messages and timestamps with a source device. The source device uses the messages and timestamps to determine a transmission delay between the source device and the system reference point device. The source device uses the transmission delay to determine a video transmission correction factor, which the source device applies to modify the time at which it outputs a signal so that the signal is aligned with signals output by other source devices when the signal arrives at the system reference point device through the IP network.