[mythtv] Closed Captioning & Teletext/Videotext

Henk Poley hpoley at dds.nl
Wed Jan 15 07:55:17 EST 2003


> Van: Erik Arendse <erik_nospam.arendse at bigfoot.com>
> 
>> At 11-1-03 06:10, Johann Klemmack wrote:
>> Does MythTV (or V4L for that matter) support closed captioning? [..]
>> Recording the text to DB would be spiffy too, and I have an idea of how
>> to do that :)
> 
> I am busy implementing Closed Captioning support and support for
> European Teletext/VideoText (used for 1000 sorts of info, including
> Closed Captioning).

Actually max. 899 sorts of things ;-)

Pages lower than 100 and higher than 999 don't exist.

> The data will probably be integrated into the recorded file into a newly 
> added frame, you could generate a searchlist from a recorded file or
> search for strings inside the frames themselves.

The question would be, can you re-generate the Teletext (CeeFax) with your
Video-Out? Other possibility would be to bitmask or alphablend it to the
displayed videostream, but that would need a Teletext viewer/interpreter.

> This way CC can be turned on/off (and selected if more than one
> language) afterwards on timeshifted TV and recorded shows.
> 
> As a by-product mythtv will have 100% buffered teletext/videotext
> support from the current selected channel, not timeshifted, but that
> would be a bit too much effort only to display a timeshifted clock :-)

Uh, how are you going to sync subtitles (?Closed Captioning?) then?

> I use AleVT as engine for the actual VBI decoding, if somebody wants to 
> strip the zvbi lib to include US based CC with the same engine perhaps 
> that's better but I don't like the lib (far too bulky).

Ah, that probably is a Teletext viewer?

	Henk Poley <><


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