Wireless Projection Vsync Synchronization to Cut Display Delay
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Solution Overview
Problem
Wireless projection systems experience significant end-to-end delays due to asynchronous display vertical synchronization signals between the source and destination devices, which degrade performance and user experience.
Innovation Solution
Adjust the display vertical synchronization signals of the destination device based on time information obtained from the source device to synchronize the synchronization signals, thereby reducing the display waiting delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless projection transmits media files from source end device to destination end device through encoding, sending, transmission, receiving, and decoding processes, then the media file can be displayed on the destination device, but significant end-to-end delay occurs due to asynchronous display vertical synchronization signals between the two devices
Solution Approach 1:
The patent implements a feedback mechanism where the destination end device monitors its own Vsync signal timing and compares it with the source end device's Vsync signal timing. Based on this feedback, the destination device dynamically adjusts its display timing to synchronize with the source device, thereby eliminating the display waiting delay and reducing overall end-to-end delay in the wireless projection system.
2Stability of the object's composition
If the destination end device waits for its Vsync signal to arrive before displaying the decoded media file, then display synchronization is maintained, but the display waiting delay increases the overall end-to-end delay
Solution Approach 1:
The patent makes the display timing dynamic by allowing the destination end device to adjust its Vsync signal phase based on the measured time difference between the source and destination devices. Instead of using a fixed waiting period, the system dynamically optimizes the display timing to minimize delay while maintaining synchronization, thereby resolving the contradiction between stability and time loss.
3Adaptability or versatility
If the source end device and destination end device operate with independent Vsync signals, then each device maintains its own display timing, but the asynchronous phase relationship causes the destination device to cannot display immediately after decoding
Solution Approach 1:
The patent merges the timing references of the source and destination devices by having the destination device adjust its Vsync signal to align with the source device's Vsync signal. This combining of timing references eliminates the asynchronous phase relationship while preserving the ability of each device to maintain its display timing, thereby removing the display waiting delay without sacrificing adaptability.
Data Source
AI summary
Embodiments of this application disclose a wireless projection method. The method includes receiving a first bitstream from a source end device, where the first bitstream is obtained by encoding first video data. The method also includes obtaining first time information of the first bitstream, where the first time information indicates a first time point at which the source end device starts encoding the first bitstream, a second time point at which the destination end device starts receiving the first bitstream, a third time point at which the destination end device starts decoding the first bitstream, or a fourth time point at which the destination end device completes decoding the first bitstream. The method also includes adjusting a display vertical synchronization (Vsync) signal of the destination end device based on the first time information.