[sci.electronics] Closed Captioning and computers

craig@gpu.utcs.utoronto.ca (Craig Hubley) (08/17/90)

I would like to find some references for closed captioning technology
(the text streams that some TV shows provide that can be picked up and
displayed on captioning cable converters).  I know this has been used
to let computers "watch TV" in the past, as in the Media Lab Personal
Newspaper project.  I think Radius has a new video-in-a-window board
that can do this, too.

I would like to know:

	- how the text stream is represented/encoded
		(I assume it is done in the extra lines/redraw interval)
		(there must be commands to 'clear screen' to display new text)
	- how the text stream is decoded at the cable converter/terminal
		(I assume it is encoded as characters and a ROM draws them)
	- whether it is possible to monitor multiple channels at once
		(perhaps by intercepting the cable prior to the converter)
	- the level of standardization of the above
		(North America wide? part of NTSC standard? world standard ?) 
	- what kind of software has been built on closed captions?
	- how widespread is closed captioning ?

	- sources of further information (email or postal contacts...)

Please mail, I will repost everything I receive.

  Craig Hubley                     kid after Live Aid: "Is that it?"
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-- 
  Craig Hubley                     kid after Live Aid: "Is that it?"
  Craig Hubley & Associates        ---------------------------------
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