VR Video Pre-Caching for Latency Reduction
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Solution Overview
Problem
Existing VR video transmission systems experience significant latency due to terminal-server request and response interactions, video decoding, and caching processes, particularly when the user viewpoint changes, which negatively impacts user experience.
Innovation Solution
A method where a client determines a recommended viewport for playing VR videos and requests corresponding video files from a server in advance, allowing for pre-caching and reducing latency during viewport switching by using media presentation descriptions, in-band event messages, and server-assisted dynamic adaptive streaming over HTTP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If viewpoint adaptive transmission is used to transmit only the main field of view, then network resource waste is reduced, but system latency increases due to request-response interaction and processing steps
Solution Approach 1:
The patent applies preliminary action by having the terminal request and cache video files corresponding to the recommended viewport in advance, before the user actually changes their viewpoint. This pre-caching mechanism ensures that when viewpoint switching occurs, the video data is already available locally, eliminating the latency caused by real-time request-response interactions and processing steps while maintaining efficient network resource usage.
2Adaptability or versatility
If all panoramic video is transmitted to support viewpoint changes, then viewpoint adaptability is maintained, but network resources are wasted on transmitting non-displayed video parts
Solution Approach 1:
The patent uses preliminary action by predicting the user's future viewpoint changes and pre-caching the corresponding video files before they are needed. This allows the system to transmit only the necessary video portions in advance rather than all panoramic video, maintaining viewpoint adaptability while significantly reducing network resource waste.
Solution Approach 2:
The patent implements feedback by using the recommended viewport information (which reflects user viewing behavior) to guide the terminal's video file selection and caching strategy. This feedback mechanism ensures that the system transmits and caches only the video portions that are likely to be viewed, optimizing the balance between viewpoint adaptability and network resource efficiency.
3Loss of energy
If video files are requested in real-time when viewpoint changes occur, then network resource efficiency is improved, but user experience deteriorates due to visible latency
Solution Approach 1:
The patent resolves this contradiction by applying preliminary action - the terminal requests and caches video files corresponding to the recommended viewport in advance, before the user actually changes their viewpoint. This pre-caching ensures that when viewpoint switching occurs, the video data is already available locally, providing seamless user experience without visible latency while maintaining efficient network resource usage.
Data Source
AI summary
Disclosed are a video transmission method, a client, and a server. The method includes: a recommended viewport for playing a virtual reality (VR) video is determined; and at least one video file corresponding to the recommended viewport is requested from a server.