HDMI Packet Encapsulation for Closed Caption Control
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Solution Overview
Problem
In digital TV systems, there is no method to carry closed caption data across digital interfaces like HDMI, forcing users to switch remote controls or device control designations to set closed caption settings, which is inconvenient and confusing.
Innovation Solution
A processor encapsulates closed caption data in packets and combines them with multimedia packets using HDMI interfaces, allowing the sink processor to selectively display closed captions based on user input, with correlation methods such as interleaving or pointers for accurate video-frame association.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If closed caption data is integrated in the TV signals before sending to the sink, then the TV remote control can be used to establish CC settings, but the source must integrate CC data in the video signals which requires switching remote controls or device control designation
Solution Approach 1:
The patent segments closed caption data from video signals into separate data packets. The source device transmits CC data and video data as distinct packet streams through the digital interface, allowing the sink device to independently process and control CC settings without requiring remote control switching between devices.
Solution Approach 2:
The patent introduces a digital packet interface as an intermediary between source and sink devices. By encapsulating CC data in standardized packets with correlation information, the system enables direct CC control at the sink device, eliminating the need for users to switch remote controls while maintaining proper synchronization with video content.
2Ease of operation
If closed caption data is sent through digital interface as separate packets, then remote control switching is eliminated, but new data structure and transmission method must be implemented
Solution Approach 1:
The patent creates a universal packet structure that can carry both video data and closed caption data through the same digital interface (HDMI). The standardized packet format with correlation fields enables multi-functional transmission, allowing existing digital interfaces to handle CC data without requiring separate dedicated channels or complex custom protocols.
Solution Approach 2:
The patent changes the data representation parameters by encoding CC data as discrete packets with specific correlation parameters rather than integrating them into video signals. This parameter transformation allows CC data to be transmitted through standard digital interfaces using modified but compatible data structures, balancing implementation feasibility with operational simplicity.
3Measurement precision
If closed caption data is correlated with video packets using interleaving or pointers, then accurate video-frame association is achieved, but data processing complexity increases
Solution Approach 1:
The patent applies preliminary action by embedding correlation information (interleaving position or pointer data) in CC packets during the transmission phase. This pre-established correlation allows the sink device to efficiently associate CC data with the correct video frames during playback without requiring complex real-time analysis or processing, thus achieving precise synchronization with manageable processing complexity.
Data Source
AI summary
Closed caption (CC) data is carried across a digital interface such as HDMI by a source such as a set top box arrange CC data into a HDMI packet that is then transmitted, along with video packets, across the interface to a sink such as a TV. The CC data is kept in the same format that it was received and the TV's decoder processor processes the packets and renders CC text as if the CC data had been received by the tuner of the TV.