Stereoscopic Playback Device Offset Control for Graphics Depth
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Solution Overview
Problem
The existing technologies for playing back 3D images are inefficient in authoring subtitles and menus, leading to increased time and effort, and require separate discs for 2D and 3D content, resulting in higher costs and potential overlap issues during playback.
Innovation Solution
A playback device that decodes main-view and sub-view video streams, graphics streams, and playlist information, using offset control metadata to adjust the depth of graphics automatically, allowing for efficient authoring and stereoscopic playback with a single plane of memory, even without separate subtitles or menus for each eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate discs for 2D and 3D content are produced, then playback compatibility is ensured, but production cost increases
Solution Approach 1:
The patent merges 2D and 3D content onto a single optical disc by storing both main-view and sub-view video streams, along with graphics streams containing depth information, in an integrated file structure. This eliminates the need for separate 2D and 3D discs while maintaining playback compatibility across different device types.
Solution Approach 2:
The optical disc is designed with universal compatibility to serve both 2D-only playback devices and 2D/3D playback devices. The disc structure includes necessary video, audio, and graphics streams that can be interpreted differently by different device types, allowing one disc to fulfill multiple playback functions without requiring separate media.
2Ease of manufacture
If depths of subtitle and menu are fixed, then authoring process is simplified, but overlap with video content occurs causing visual issues
Solution Approach 1:
The patent implements dynamic depth adjustment for graphics elements by storing depth information in the graphics stream that can be modified in real-time during playback. The playback device reads depth values from the graphics stream and adjusts the Z-coordinate positioning of subtitles and menus dynamically, allowing them to move behind or in front of video content as needed without requiring complex pre-authoring for each scenario.
Solution Approach 2:
The system changes the depth parameter (Z-coordinate) of graphics elements dynamically based on values stored in the graphics stream. By modifying the depth parameter during playback rather than fixing it during authoring, the system prevents overlap issues while keeping the authoring process relatively simple. The graphics stream contains control information that allows runtime adjustment of graphic element positions in the depth dimension.
3Measurement precision
If control information is stored in each of 32 graphics streams, then depth control precision is improved, but access time increases due to wasteful processes
Solution Approach 1:
The patent extracts depth control information from individual graphics streams and consolidates it into a separate depth information stream. This allows the playback device to read only the necessary depth values from the consolidated stream rather than accessing multiple graphics streams, significantly reducing access time while maintaining precise depth control for all graphics elements.
Solution Approach 2:
The system introduces a depth information stream as an intermediary that contains pre-processed depth control data for all graphics elements. This intermediary stream acts as a central repository that the playback device can access efficiently, eliminating the need to parse through multiple graphics streams to find depth information, thus reducing access time while preserving precision.
4Measurement precision
If left-view and right-view graphics are created separately, then stereoscopic accuracy is improved, but authoring time and effort increase enormously
Solution Approach 1:
The patent segments the graphics rendering process into two independent rendering passes: first rendering the main-view graphics with depth information, then rendering the sub-view graphics by applying parallax offset to the same graphics data. This segmentation allows the authoring process to create graphics once and automatically generate both left-view and right-view versions, maintaining stereoscopic accuracy while dramatically improving authoring efficiency.
Solution Approach 2:
The system performs preliminary rendering of graphics elements with depth information stored in the graphics stream. During actual playback, the playback device uses this pre-rendered graphics data and applies view-dependent transformations (parallax offset) to generate the appropriate left-view and right-view images. This preliminary action eliminates the need for manual creation of separate graphics for each view, reducing authoring effort while maintaining accuracy.
Data Source
Figure 1A~1C
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AI summary
The present invention provides a playback device for playing back a main-view video stream, a sub-view video stream, and a graphics stream in accordance with playlist information. The main-view video stream includes picture data constituting a main view of a stereoscopic image and the sub-view video stream includes picture data constituting a sub view of the stereoscopic image. The playlist information includes control information that defines an offset control to be applied when graphics data is overlaid with picture data.