360 VR Video Decoder Syntax Parsing for Content Rotation
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Solution Overview
Problem
360-degree image/video content represented in a 360 VR projection format experiences poor compression efficiency due to moving objects being split and/or stretched, necessitating an innovative approach to enhance coding efficiency.
Innovation Solution
A method and apparatus that include a video processing system with a video decoder capable of parsing syntax elements to obtain rotation information for content-oriented rotation, allowing for improved compression efficiency by rotating the 360-degree image/video content and signaling this rotation information within the bitstream, enabling decoder-side inverse rotation for rendering and display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 360-degree image/video content is represented in a 360 VR projection format, then the content can be displayed with wide field of view for immersive VR experiences, but moving objects are split and stretched resulting in poor compression efficiency
Solution Approach 1:
The patent applies dynamic rotation transformation to the 360-degree content based on the orientation of moving objects. Instead of using a fixed projection format, the system dynamically adjusts the content orientation through rotation matrices to align moving objects with the projection coordinates, thereby reducing splitting and stretching artifacts while maintaining wide field of view display capability
Solution Approach 2:
The patent changes the orientation parameters of the 360-degree content by applying rotation transformations. The rotation angles and axes are adjusted based on the motion vectors and object orientation, transforming the content from a fixed projection format to a dynamically oriented representation that improves compression efficiency while preserving the immersive display quality
2Productivity
If content-oriented rotation is applied to improve compression efficiency, then bitrate is reduced, but the complexity of parsing syntax elements and processing rotation information increases
Solution Approach 1:
The patent segments the rotation information into separate syntax elements within the bitstream. The rotation parameters are encoded as distinct data structures that can be independently parsed and processed, allowing the decoder to efficiently extract rotation information without processing the entire bitstream, thereby reducing the complexity burden while achieving bitrate reduction
Solution Approach 2:
The patent introduces syntax elements as intermediary data structures that carry rotation information between the encoder and decoder. These syntax elements act as mediators that standardize the transmission of rotation parameters, simplifying the parsing process by providing a structured interface for extracting rotation information without requiring complex direct processing of the original content
Data Source
AI summary
A video processing method includes receiving a bitstream, processing the bitstream to obtain at least one syntax element from the bitstream, and decoding the bitstream to generate a current decoded frame having a rotated 360-degree image/video content represented in a 360-degree Virtual Reality (360 VR) projection format. The at least one syntax element signaled via the bitstream indicates rotation information of content-oriented rotation that is involved in generating the rotated 360-degree image/video content, and includes a first syntax element. When the content-oriented rotation is enabled, the first syntax element indicates a rotation degree along a specific rotation axis.