[54] APPARATUS AND METHODS FOR
AVOIDING LOSS OF CLOSED CAPTION
DATA WHEN USING EXTENDED DATA
SERVICES
[75] Inventors: Henry C. Yuen, Redondo Beach;
Daniel S. Kwoh, La Canada; Wing P.
Leung, Arcadia; Tony T. Tarn,
Hawthorne, all of Calif.
[73] Assignee: Index Systems, Inc., Virgin Islands
(Br.)
[21] Appl. No.: 265,709
[22] Filed: Jun. 24,1994
Related U.S. Application Data
[63] Continuation-in-part of Ser. No. 253,153, Jun. 2, 1994.
[51] Int. CI.6 H04N 7/088
[52] U.S. CI 348/478
[58] Field of Search 348/478, 563,
348/476, 473, 468; H04N 7/87, 7/88
[56] References Cited
U.S. PATENT DOCUMENTS
4,855,827 8/1989 Best 348/478
5,237,412 8/1993 Nakajima 348/478
5,347,318 9/1994 Kobayashi 348/478
5,371,545 12/1994 Tults 348/478
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 second data into the second vertical blanking interval VBI line. Another method for inserting data into VBI lines includes the steps of testing whether data is being inserted into a first VBI line, and inserting any data into VBI lines adjacent to the first VBI line in 2X format rather than IX format, if data is being inserted into the first VBI line.
30 Claims, 13 Drawing Sheets
