VR Display Refresh Offset for Multi-HMD Resource Contention
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Solution Overview
Problem
Virtual Reality (VR) systems face challenges in managing resource contention and synchronization when multiple Head Mounted Displays (HMDs) are connected, leading to potential judder and nausea due to delayed image rendering, as existing solutions like asynchronous time warp and gen lock are inadequate for predictable pacing of display operations across multiple HMDs.
Innovation Solution
A method is introduced to determine and impose a selected refresh offset and dynamic refresh rate for multiple VR displays to avoid resource conflicts, allowing for staggered refresh times and dynamic adjustments based on real-time processing needs, such as asynchronous time warp requests, ensuring consistent latency across connected HMDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple HMDs are connected to a VR system, then the system can support more users simultaneously, but resource contention increases causing judder and nausea
Solution Approach 1:
The patent segments the display refresh operations of multiple HMDs by introducing refresh offsets. Each HMD is assigned a specific offset value that divides the refresh period into distinct time slots, ensuring that resource-intensive operations (such as asynchronous time warp requests) are distributed across different time intervals rather than competing simultaneously. This temporal segmentation eliminates resource contention while maintaining support for multiple HMDs.
Solution Approach 2:
The patent implements dynamic refresh rate adjustment based on real-time system conditions. The refresh rate is modified dynamically to accommodate competing resource needs of multiple HMDs, allowing the system to adaptively pace display operations. This dynamic adjustment ensures that each HMD receives adequate processing resources while maintaining overall system stability and preventing judder.
2Stability of the object's composition
If refresh rates are synchronized across multiple HMDs, then display timing is consistent, but resource contention causes delays and judder
Solution Approach 1:
The patent applies preliminary action by pre-calculating and assigning refresh offsets to each HMD before operation begins. These offsets are determined in advance to distribute resource contention across different time slots. By preparing the timing schedule beforehand, the system avoids real-time conflicts during actual display operations, ensuring both timing consistency and adequate processing time for each HMD.
3Speed
If asynchronous time warp requests are processed for multiple HMDs simultaneously, then each HMD gets real-time updates, but resource contention degrades performance
Solution Approach 1:
The patent implements periodic action by structuring HMD refresh operations in regular intervals with predetermined offsets. Each HMD processes asynchronous time warp requests at specific periodic intervals determined by its assigned offset. This periodic structure ensures that while each HMD receives timely updates, the overall processing throughput is maintained by distributing the computational load across different time periods rather than processing all requests simultaneously.
Data Source
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AI summary
Various virtual reality computing systems and methods are disclosed. In one aspect, a method of delivering video frame data to multiple VR displays (HMD1, HMD2) is provided. The method includes generating content for multiple VR displays and sensing for competing needs for resources with real time requirements of the multiple VR displays. If competing needs for resources with real time requirements are sensed, a selected refresh offset for refreshes of the multiple VR displays is determined to avoid conflict between the competing needs for resources of the multiple VR displays. The selected refresh offset is imposed and the content is delivered to the multiple VR displays.