Closed Captioning Data Tunneling for Ancillary Metadata Preservation
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Solution Overview
Problem
Audio-video content providers face challenges in embedding and preserving ancillary data, such as URLs and metadata, within digital television signals, as this data often gets stripped during processing at satellite or cable headends, disrupting its delivery to receivers.
Innovation Solution
The implementation of the CEA-708 advanced closed captioning protocol to include data packets that are disregarded by legacy receivers, utilizing hidden caption windows and specific indicators to embed ancillary data within the closed captioning channel, ensuring it survives processing and is retrievable by compatible devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ancillary data is embedded in digital TV signals using traditional methods, then data delivery is intended, but data gets stripped during processing at headends
Solution Approach 1:
The patent uses closed captioning data as an intermediary carrier to transport ancillary data. Instead of embedding ancillary data directly in the video signal where it gets stripped, the invention embeds it within the closed captioning channel which is processed differently and preserved through headend operations. This intermediary approach allows ancillary data to survive the distribution chain.
Solution Approach 2:
The patent embeds ancillary data within the closed captioning data structure, creating a nested configuration where ancillary data is contained inside the closed captioning channel which itself is part of the digital TV signal. This nested structure protects the inner ancillary data by using the outer closed captioning layer as a protective container that survives headend processing.
2Reliability
If closed captioning channel is used to embed ancillary data, then data preservation is achieved, but compatibility with legacy receivers must be maintained
Solution Approach 1:
The patent applies local quality by making the closed captioning data structure have different properties for different receivers. Modern receivers with CEA-708 support can decode and extract the ancillary data from the closed captioning channel, while legacy receivers simply display or ignore the closed captioning data without attempting to extract ancillary information. Each receiver type interacts with the same signal structure in the way appropriate for its capabilities.
Solution Approach 2:
The patent segments the closed captioning data structure into functional components: essential closed captioning content that all receivers need, and ancillary data sections that modern receivers can extract. The ancillary data is embedded within specific fields of the closed captioning data structure (such as service description or program description fields) without disrupting the overall closed captioning functionality for legacy devices.
Data Source
AI summary
An example apparatus that processes DTVCC data has a demultiplexer that extracts DTVCC data packets from a DTV signal. A parser parses the DTVCC data packets by: passing normal DTVCC data to a CC decoder; detecting ancillary data in the DTVCC data packets; and separating the ancillary data from the DTVCC data for output to an ancillary data process. An apparatus that processes DTVCC data has an ancillary data packager that packages data ancillary to DTV data for insertion into the DTVCC data packets. A DTVCC data packager receives CC data into DTVCC data packets and packages the ancillary data together with the DTVCC data into DTVCC data packets. A multiplexer multiplexes the DTVCC data packets from the DTVCC data packager with non-CCDTV data to produce DTV signal data. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.