[mythtv-users] Teletext Extra (UK)

Andrew Sayers andrew-mythtv-users at pileofstuff.org
Tue Jan 22 02:20:00 UTC 2008

John Veness wrote:
> I've become intrigued by Teletext Extra, a service broadcast on Freeview 
> (DVB-T) here in the UK. http://www.teletextextra.co.uk/ has some details.
> Does anyone know how this works technically, and whether the new stuff 
> can be incorporated into Myth? It looks to me like it's a compiled 
> application for certain set-top boxes, rather than an open-standard 
> thing like MHEG, but I could be wrong.
> Cheers,
> John

I haven't a clue how it works, but here are some facts that may or may
not be useful:

We've got a cheapo Tesco set-top box in a different room to my Myth box.
 When we bought it, it only supported the ordinary 7 day guide.  At some
point, it started popping up messages about (what I assume was) a
firmware upgrade for the box.  The popups seemed to occur while channel
surfing, so my guess is that one of the teletext channels broadcasts a
firmware upgrade as some sort of data stream.

After a few weeks of being nagged by the STB, I downloaded the upgrade
(over the airwaves), and got Teletext Extra installed as my default
guide.  This suggests to me that:

a) as you say, it requires special plumbing in the STB in order for it
to work
b) If you can find the firmware upgrade in the airwaves, then you might
be able to decipher some useful information from that.

After upgrading my firmware, my STB has taken on some new habits:

a) It wants to be left on and plugged in at all times, because it needs
to redownload the complete listings every time it's turned on
b) Downloading the listings takes several minutes, and (if memory
serves), the STB needs to be in standby mode during that time
c) When downloading new listings, the red "standby" LED is lit up, but
the green "on" LED will flash momentarily about once a second.
Presumably this means that it's downloading then processing some guide
data?  Maybe the data is compressed?
d) Sometimes, it flashes the green LED in a similar way when it's in
standby mode normally.  Presumably it's updating guide data?

To be honest, I find the whole thing rather user-unfriendly.  It's also
advertising-supported, so I would expect Teletext Limited to be very
happy about people putting their product in other places, just so long
as you don't make the guide data available independently of the grabber.

	- Andrew

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