Re: [stella] Closed Captioning Query

Subject: Re: [stella] Closed Captioning Query
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Tue, 20 Aug 2002 23:20:56 +0200
> BTW, the hard copy of EIA-608 is only $60 now (50 plus $10 S&H) because
> it's been superceded by the new spec (which is mostly just stuff related
> digital video, big deal) but I am still reluctant to buy it if it turns
> the 2600 can't do what it needs to do -- based on what we can glean right
> How curious is everyone regarding CC?

CC is a North-American standard. Over here in Europe subtitling is
a feature of Teletext. Unless you have a PC TV-card with CC software,
it's very difficult to find a decoder for closed captioning outside of
the USA/Canada. So I suppose most of the non-american programmers here
won't be able to help you figuring things out.

To say whether the VCS can do CC or not we would need some more
information about how line 21 is supposed to look. The VCS surely
can do 16 pixels per scanline. If it can do them in the right place
depends on where the right places are. But since the resolution is
so low, and the decoder probably checks for the center of the pixels,
it might be possible that the VCS would be able to do "good enough"
encoding for CC.

> To describe the bit encoding system in terms of white and black zones on
> the scanline probably only takes a couple brief paragraphs, which kinda
> sucks to have to buy an expensive book just for that but there is just
> NOTHING on the internet that explains it in these terms.  They always
> assume we've already got the bits out (like the character set listings).

There are several GPL projects for Linux software for PC TV-cards. Some
of them can do CC and Teletext decoding. If you can't find the nessessary
information online, you could email some of the programmers in those
projects and ask them for more details.

Ciao, Eckhard Stolberg

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