Multi-Port Video Frame Synchronization Using Timing Feedback
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Solution Overview
Problem
In video systems, variations in devices, distances, and transmission protocols cause misalignment of video frames arriving at sink or repeater devices, leading to synchronization issues and computational overhead in aligning source devices.
Innovation Solution
A method and system for video frame synchronization using closed-loop digital timing commands to adjust the arrival times of video frames across multiple ports, allowing for synchronization by determining offset correction factors and sending commands to modify transmission times, enabling alignment of video frames to a common time or desired offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If video streams are transmitted over data links with variations in devices, distances, and transmission protocols, then the video streams can be transmitted to multiple ports, but the video frames arrive misaligned and out of synchronization
Solution Approach 1:
The system performs preliminary timing measurements and offset calculations before final frame processing. The sink device measures arrival time offsets and determines correction factors in advance, then communicates these to source devices to pre-adjust their transmission timing, preventing synchronization issues before they occur.
Solution Approach 2:
The system implements a feedback loop where the sink device continuously monitors frame arrival times, calculates synchronization offsets, and sends alignment commands back to source devices. This closed-loop feedback mechanism enables continuous correction of timing misalignment, maintaining synchronization despite variations in transmission conditions.
2Manufacturing precision
If source devices communicate with each other to synchronize video streams, then frame alignment can be achieved, but significant computational overhead is required
Solution Approach 1:
The sink device acts as an intermediary that centralizes the synchronization coordination function. Instead of source devices communicating directly with each other (requiring multiple communication channels and complex coordination), the sink device receives timing information from all sources, calculates offsets, and distributes correction commands, simplifying the overall system architecture and reducing computational overhead at source devices.
Solution Approach 2:
Each source device independently adjusts its own transmission timing based on correction factors received from the sink device. This self-service approach eliminates the need for complex inter-source communication and coordination protocols, reducing computational overhead while maintaining synchronization accuracy.
3Speed
If video frames are transmitted without timing correction, then transmission speed is maintained, but port-switching time and picture-in-picture display quality deteriorate
Solution Approach 1:
The system pre-calculates and communicates timing correction factors to source devices before frame transmission. This allows source devices to adjust their transmission timing in advance, ensuring that frames arrive synchronized without requiring post-reception processing or buffering, thus maintaining transmission speed while improving port-switching reliability.
Data Source
AI summary
Embodiments of the invention are generally directed to video frame synchronization. An embodiment of a method includes receiving a first video data stream from a first source at a first port of a multi-port device, a first video frame of the first video data stream arriving at the first port at a first arrival time, and receiving a second video data stream from a second source at a second port of the multi-port device, a second video frame of the second video data stream arriving at the second port at a second arrival time. The method further includes determining an offset between the first arrival time and the second arrival time, determining one or more correction factors based at least in part on the offset, the one or more correction factors including a first correction factor for the first source, and sending a first command to the first source to modify a time of transmission by the first source of a third video frame following the first frame using the correction factor.