3D Overlay Depth Encoding in CEA-708-D Closed Captioning
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Solution Overview
Problem
Current Digital TV closed captioning standards, such as CEA-708-D, lack the capability to specify the depth for on-screen display of caption data in 3D rendering systems, which are becoming increasingly prevalent with newer digital TV systems using polarized glass and shuttered glasses for depth projection.
Innovation Solution
The method involves encoding and transmitting overlay depth data as a fraction of the viewer's distance within the available portions of a multilayer protocol system, specifically utilizing unallocated elements of the CEA-708-D standard, such as the packet, service, or coding layers, to support depth adjustment for stereoscopic displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing CEA-708-D captioning technology is used, then compatibility with legacy systems is maintained, but the capability to specify depth for on-screen display of caption data in 3D rendering systems is lost
Solution Approach 1:
The patent embeds depth information within existing CEA-708-D protocol structures by utilizing reserved or unallocated fields in the captioning data stream. This nesting approach allows depth specification to be carried within the existing protocol framework without requiring a separate communication channel or fundamentally altering the protocol structure, thereby maintaining legacy compatibility while adding 3D depth capability.
Solution Approach 2:
The patent introduces new parameters (depth values) into the existing captioning protocol by repurposing reserved fields or extending existing data structures. This parameter extension allows the system to convey depth information for stereoscopic displays while maintaining the original protocol's structure and compatibility with legacy systems that ignore the new parameters.
2Adaptability or versatility
If overlay depth data is transmitted using available portions of multilayer protocol system, then depth adjustment for stereoscopic displays is enabled, but data transmission complexity increases
Solution Approach 1:
The patent segments the captioning data transmission into distinct layers (video layer, audio layer, and data layer) within the multilayer protocol system. Overlay depth information is transmitted in the data layer, separate from the core captioning content. This segmentation allows depth data to be added without complicating the existing video and audio transmission paths, enabling stereoscopic display support while maintaining relatively simple data transmission.
3Adaptability or versatility
If reserved fields in CEA-708-D standard are utilized for depth information, then standard extension is achieved, but precision of depth data representation may be limited
Solution Approach 1:
The patent uses only a portion of the available reserved fields in the CEA-708-D standard to carry depth information, rather than attempting to encode all possible depth parameters. This partial action approach allows the system to achieve sufficient depth precision for practical stereoscopic display applications while maintaining full compatibility with the existing standard structure. The depth data is represented using a simplified format that fits within the constrained field sizes.
Data Source
AI summary
Methods for carrying and transmitting overlay depth data of an overlay of a stereoscopic image of a display device as a fraction of a viewer distance from the overlay are described.