Apparatus and methods for avoiding loss of closed caption data when using extended data services
US5543852A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1994 |
| Grant date | Aug 6, 1996 |
| Priority date | — |
| Expiry date | Jun 24, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/445
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus and methods are provided for inserting data into a vertical blanking interval (VBI) line of video frames. The method includes the steps of inserting first data into a first vertical blanking interval VBI line for a plurality of consecutive video frames, inserting second data into a second vertical blanking interval VBI line for a plurality of consecutive video frames, counting a number of consecutive video frames having first data inserted into the first vertical blanking interval VBI line, terminating the insertion of first data for a first number of video frames before again inserting first data into the first vertical blanking VBI interval line when the counted number of consecutive video frames into which first data is inserted into the first vertical blanking interval VBI line equals a second number, and repeating the steps. In a specific embodiment the method includes the steps of detecting when the insertion of second data into the second vertical blanking interval VBI line terminates, and terminating for a second number of video frames the insertion of first data into the first vertical blanking interval VBI line upon detecting the termination of insertion of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.