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Adventures in Teletext Recovery (andrewnile.co.uk)
92 points by bilekas 11 months ago | hide | past | favorite | 34 comments

No mention of Teletext / Ceefax is complete without derailment of the topic at hand by plugging the music of the incomparable Ceephax Acid Crew


Also..: I'm really surprised to learn old VHS tapes can contain embedded teletext signals! Very cool article.

Thats what blew me away! I was reading something on the Closed Caption that were encoded into the broadcast / videos for subtites and realised it was those scanlines you see. Then from a rabbit hole of a day found these guys restoring the data from recorded TV streams! Incredible!


> Also..: I'm really surprised to learn old VHS tapes can contain embedded teletext signals! Very cool article.

Holy cow that’s awesome, and really goes to show why archivists must be so diligent in their preservation efforts.

Now that's what I call retrocomputing! Too bad the date on the teletext pages doesn't include the year... when was the premiere of season (pardon me, series) 3 of Babylon 5 again? Ah, 1996 (thanks Wikipedia!).

To think teletext is still around today, a fossilized technology using a standard that has been almost unchanged for 40 years! Although nowadays I mostly read it using a smartphone app - the bite-size pages are perfect for a quick and (almost) ad-free news update.

As someone who was a toddler when those "screenshots" were live, teletext is one of my favorite sources of information. Mostly because very few people read it, therefore the news are straight to the point with comparatively low political bullshit.

I read it with a python script I wrote myself that parses images into ANSI sequences and outputs them to a terminal. If I manage to put the code in a presentable state it could be a cool "show HN".

Please do this.

The episode they refer to "Shadow Dancing" was broadcast in the UK on 15th Sep (from teletext)

And usenet confirms



That it was 1996 was the year


Says it was first broadcast in the US on 21st October 1996

Was B5 really broadcast in the UK ahead of the US?!

Star Trek in that era was months to years behind -- evidence in November 1997


BBC (free to air) were broadcasting episodes first shown in the US in June 1996, and Sky (Pay TV) were on October 1996.

This gave me a real hit of nostalgia. All the more so as my mum (who died a couple of years ago) was a fan of Babylon 5. Sadly in her last years her own signal faded and became indecipherable.

I remember that as a teenager I did observe that in some cases, I was able to see partial teletext pages from VHS tapes recorded from TV (like a few characters of the date/time in the top row that did make some sense).

Now, seeing that it's actually possible to recover that data... I find it's too bad that we threw away all those tapes because nobody was watching them any more.

Right, I had (wrongly?) assumed that the Teletext signal had been mangled during recording. Maybe some VHS machines recorded and played back Teletext flawlessly? Or maybe it was being mangled during playback?

It's a shame that the teletext archive doesn't offer raw downloads and the online browser is the only available option.

Ah, Digitiser, I used to read you every day. Occasionally Teletext would do multiple choice adventures, complete with ASCII art. And very little in the modern world can capture the excitement and terror of waiting for the football scores to turn the page and show if there was a new score in the Everton game.

Worth mentioning alt.digitiser on Usenet where the unaware would turn up looking for help with their digitisers[0]. Fun times on IRC with some now-internet-famous people who I won’t dox - I know you’re all here.

[0] https://en.m.wikipedia.org/wiki/Graphics_tablet

I hung out in the #digi channel around 1997-1999.

Recently-ish (2016 I think) I logged back in out of curiosity.

Some of the same names were still there, chatting away.

Around ‘94 you could “download” games over satellite (BSkyB) links and play them. They were higher rez than this article has and far more dynamic. I got so good at the darts game.

This is a wonderful trip down memory lane <3

You can go back even further. If you had a BBC Micro, you could buy a Teletext unit to attach to it and download software over Teletext via system called "Prestel": https://www.youtube.com/watch?v=wq53DO7zL_g

I have vague memories of my dad managing to "hack" this system and get software for free as he worked out they used a simple XOR cipher on the BASIC source code sent over the air and most programs started with "10"!

Prestel was a Viewdata service over dialup modem (usually V.23 1200/75 bps ones). The screen rendering looks a lot like Teletext but fundamentally this is completely different technology.

Aha! I was only 5-6 years old, so my memory is probably fuzzy :-) I do remember it had a Teletext box like https://en.wikipedia.org/wiki/BBC_Micro_expansion_unit#/medi... .. I also recall he would issue commands by dialling up but then download software that came over the air.

I did some Googling and it may not have been Prestel (which he did also use) but something called "Telesoftware" – https://en.wikipedia.org/wiki/Telesoftware – which involved software being distributed over Ceefax.

I recall a couple of things from 34 years ago:

- If you used Micronet (a part within the broader Prestel system) between midnight and 8am, you weren't charged for the phone call [I guess this was easy to implement because BT ran both Prestel/Micronet and the phone system)

- The phone number for 'The Gnome at Home' BBS was 888-8894

- A kind person I met on a BBS sent me a cassette in the mail that had software to upload data at 1200 baud (half duplex, as the modem couldn't do 1200/1200).

I remember running up a bill for £27 playing Shades on Micronet; seemed like a lot of money back then.

It was a lot of money!

I'd guess you might be thinking of the darts game that Playjam had. This was on Sky Digital rather than analogue Sky, so more like 1998-1999. From memory the old analogue system didn't have any interactive features.

I got addicted to that too, and Beehive Bedlam in 2001.

I love TV tech. The old Teletext / Ceefax product was pretty impressive for its time and some insane engineering. I spent a number of years writing software for the TV industry (both backend and STB software) as a result of playing about with this when I was younger.

My brother was so disappointed at losing Beehive Bedlam when we switched from Sky to NTL in ~2002. I remember asking around for something similar and he subsequently was hooked on Bust-a-Move for about 2 years. Music still etched on my brain.

Fun times.

For files of captured video containing teletext, there is ccextractor to pull it out:


I've never tried ccextractor for pulling teletext but I use it for pulling almost any kind of closed captions.

Teletext is still around and updated here in Norway. I still use it sometimes to read news, mostly for the nostalgia.

The NOS (Dutch Broadcasting Foundation) still provides Teletext via their website[1] that is still used quite a lot for its short format. There is also a public API[2]

[1]: https://nos.nl/teletekst [2]: https://teletekst-data.nos.nl/json

Same for Finnish public broadcasting: https://yle.fi/aihe/tekstitv

Some picks:

English news: https://yle.fi/aihe/tekstitv?P=190

Seasonal calendar: https://yle.fi/aihe/tekstitv?P=830

Museum of Teletex Art: https://yle.fi/aihe/tekstitv?P=805

Getting some major ANSI / Prodigy vibes

You Americans have definitely missed on teletext, it's funny that you're comparing it to Prodigy (to be fair you have two-way systems, but teletext are much more accessible, being built on TV). It actually influenced how CC/subtitles looked: since US captions don't have colour, you rely on moving it closer to the speaker and on writing names in-stream while British subtitles (especially of BBC specification) also used colours.

Edit: but I think that the true winner of this era is the French, they have both (https://en.wikipedia.org/wiki/Minitel, IEEE has a nice, although a bit opinionated, summary: https://web.archive.org/web/20171004160220/https://spectrum....)

I had a toast-rack ZX Spectrum as my childhood computer but grew up in North America, and just made the connection how much the TT graphics look like Spectrum graphics.

Unrelatedly, Canada had a late launch of Minitel-like services in the mid-1990s: https://techmonitor.ai/technology/bell_canada_launches_inter...


Unrelated, but imagine if smartphones today were instead called screenphones. Fun!

I think that the reason teletext never went live in NA (although to be fair CBC had some serious trials) is because of different broadcast standards. Not in "NTSC versus PAL" mind you, but in "nationally-run versus autonomous affiliates of networks" sense. Convincing many independent stations to install equipment and to update the information for a nebulous service that you aren't sure that the viewers who bought their sets would appreciate, while across the pond the cost of switching to televisions with teletext is (for most people) call your renter if they have one available for you to swap to while we BBC/IBA (the Independent Broadcasting Authority) will take care of our side, even if you're in the Channel Islands.

This is lost to history, that there was a point when many CBC stations were affiliates and not actually run by CBC themselves.

Canada also experimented with the Telidon system in the 1970s, which had some similarities to Teletext:


I enjoyed this before the Internet. You had tv-schedules, news, horoscope and some other things too.

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