6 ms·

Adventures in Teletext Recovery

92 points by bilekas 4y ago

isoprophlex 4y ago
No mention of Teletext / Ceefax is complete without derailment of the topic at hand by plugging the music of the incomparable Ceephax Acid Crew http://www.ceephax.co.uk/ http://www.ceephax.co.uk/ Also..: I'm really surprised to learn old VHS tapes can contain embedded teletext signals! Very cool article.
- bilekas 4y ago
  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! https://archive.teletextarchaeologist.org/ https://archive.teletextarchaeologist.org/
- jl6 4y ago
  > 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.
ale42 4y ago
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.
- rahimnathwani 4y ago
  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?
dayjah 4y ago
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
- petercooper 4y ago
  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 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"!
  - NovemberWhiskey 4y ago
    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.
    - rahimnathwani 4y ago
      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).
      - NovemberWhiskey 4y ago
        I remember running up a bill for £27 playing Shades on Micronet; seemed like a lot of money back then.
rob74 4y ago
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.
- iso1631 4y ago
  The episode they refer to "Shadow Dancing" was broadcast in the UK on 15th Sep (from teletext) And usenet confirms https://groups.google.com/g/uk.media.tv.sf.babylon5/c/_6WzOCiRSE8/m/rPdypUzHn_MJ https://groups.google.com/g/uk.media.tv.sf.babylon5/c/_6WzOC... https://groups.google.com/g/uk.media.tv.sf.babylon5/c/KxNjFfe_Rn4/m/2-ng-AEvun8J https://groups.google.com/g/uk.media.tv.sf.babylon5/c/KxNjFf... That it was 1996 was the year https://babylon5.fandom.com/wiki/Shadow_Dancing https://babylon5.fandom.com/wiki/Shadow_Dancing 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 https://groups.google.com/g/uk.media.tv.sf.startrek/c/apVB4RNP95w/m/l9h91XYD_60J https://groups.google.com/g/uk.media.tv.sf.startrek/c/apVB4R... BBC (free to air) were broadcasting episodes first shown in the US in June 1996, and Sky (Pay TV) were on October 1996.
- qsort 4y ago
  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".
  - jbaber 4y ago
    Please do this.
klondike_klive 4y ago
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.
raldi 4y ago
Getting some major ANSI / Prodigy vibes
- zinekeller 4y ago
  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 https://en.wikipedia.org/wiki/Minitel, IEEE has a nice, although a bit opinionated, summary: https://web.archive.org/web/20171004160220/https://spectrum.ieee.org/tech-history/cyberspace/minitel-the-online-world-france-built-before-the-web https://web.archive.org/web/20171004160220/https://spectrum....)
  - xattt 4y ago
    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_interactive_screen_phone_services https://techmonitor.ai/technology/bell_canada_launches_inter...
    - cf100clunk 4y ago
      Canada also experimented with the Telidon system in the 1970s, which had some similarities to Teletext: https://wikiless.org/wiki/Telidon https://wikiless.org/wiki/Telidon
    - zinekeller 4y ago
      > INTERACTIVE SCREEN PHONE 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.
sourcecodeplz 4y ago
I enjoyed this before the Internet. You had tv-schedules, news, horoscope and some other things too.
peppermint_gum 4y ago
It's a shame that the teletext archive doesn't offer raw downloads and the online browser is the only available option.
thom 4y ago
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.
- 0898 4y ago
  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.
- jl6 4y ago
  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 https://en.m.wikipedia.org/wiki/Graphics_tablet
mtlmtlmtlmtl 4y ago
Teletext is still around and updated here in Norway. I still use it sometimes to read news, mostly for the nostalgia.
- cornedor 4y ago
  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 https://nos.nl/teletekst [2]: https://teletekst-data.nos.nl/json https://teletekst-data.nos.nl/json
  - Ekaros 4y ago
    Same for Finnish public broadcasting: https://yle.fi/aihe/tekstitv https://yle.fi/aihe/tekstitv Some picks: English news: https://yle.fi/aihe/tekstitv?P=190 https://yle.fi/aihe/tekstitv?P=190 Seasonal calendar: https://yle.fi/aihe/tekstitv?P=830 https://yle.fi/aihe/tekstitv?P=830 Museum of Teletex Art: https://yle.fi/aihe/tekstitv?P=805 https://yle.fi/aihe/tekstitv?P=805
cf100clunk 4y ago
For files of captured video containing teletext, there is ccextractor to pull it out: https://ccextractor.org/public/general/whatsccextractor/ https://ccextractor.org/public/general/whatsccextractor/ I've never tried ccextractor for pulling teletext but I use it for pulling almost any kind of closed captions.

92 points by bilekas 4y ago

No mention of Teletext / Ceefax is complete without derailment of the topic at hand by plugging the music of the incomparable Ceephax Acid Crew http://www.ceephax.co.uk/ http://www.ceephax.co.uk/ Also..: I'm really surprised to learn old VHS tapes can contain embedded teletext signals! Very cool article.

bilekas 4y ago
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! https://archive.teletextarchaeologist.org/ https://archive.teletextarchaeologist.org/
jl6 4y ago
> 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.

ale42 4y ago

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.

rahimnathwani 4y ago
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?

dayjah 4y ago

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

petercooper 4y ago
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 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"!
- NovemberWhiskey 4y ago
  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.
  - rahimnathwani 4y ago
    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).
    - NovemberWhiskey 4y ago
      I remember running up a bill for £27 playing Shades on Micronet; seemed like a lot of money back then.

rob74 4y ago

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.

iso1631 4y ago
The episode they refer to "Shadow Dancing" was broadcast in the UK on 15th Sep (from teletext) And usenet confirms https://groups.google.com/g/uk.media.tv.sf.babylon5/c/_6WzOCiRSE8/m/rPdypUzHn_MJ https://groups.google.com/g/uk.media.tv.sf.babylon5/c/_6WzOC... https://groups.google.com/g/uk.media.tv.sf.babylon5/c/KxNjFfe_Rn4/m/2-ng-AEvun8J https://groups.google.com/g/uk.media.tv.sf.babylon5/c/KxNjFf... That it was 1996 was the year https://babylon5.fandom.com/wiki/Shadow_Dancing https://babylon5.fandom.com/wiki/Shadow_Dancing 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 https://groups.google.com/g/uk.media.tv.sf.startrek/c/apVB4RNP95w/m/l9h91XYD_60J https://groups.google.com/g/uk.media.tv.sf.startrek/c/apVB4R... BBC (free to air) were broadcasting episodes first shown in the US in June 1996, and Sky (Pay TV) were on October 1996.
qsort 4y ago
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".
- jbaber 4y ago
  Please do this.

klondike_klive 4y ago

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.

raldi 4y ago

Getting some major ANSI / Prodigy vibes

zinekeller 4y ago
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 https://en.wikipedia.org/wiki/Minitel, IEEE has a nice, although a bit opinionated, summary: https://web.archive.org/web/20171004160220/https://spectrum.ieee.org/tech-history/cyberspace/minitel-the-online-world-france-built-before-the-web https://web.archive.org/web/20171004160220/https://spectrum....)
- xattt 4y ago
  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_interactive_screen_phone_services https://techmonitor.ai/technology/bell_canada_launches_inter...
  - cf100clunk 4y ago
    Canada also experimented with the Telidon system in the 1970s, which had some similarities to Teletext: https://wikiless.org/wiki/Telidon https://wikiless.org/wiki/Telidon
  - zinekeller 4y ago
    > INTERACTIVE SCREEN PHONE 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.

sourcecodeplz 4y ago

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

peppermint_gum 4y ago

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

thom 4y ago

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.

0898 4y ago
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.
jl6 4y ago
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 https://en.m.wikipedia.org/wiki/Graphics_tablet

mtlmtlmtlmtl 4y ago

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

cornedor 4y ago
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 https://nos.nl/teletekst [2]: https://teletekst-data.nos.nl/json https://teletekst-data.nos.nl/json
- Ekaros 4y ago
  Same for Finnish public broadcasting: https://yle.fi/aihe/tekstitv https://yle.fi/aihe/tekstitv Some picks: English news: https://yle.fi/aihe/tekstitv?P=190 https://yle.fi/aihe/tekstitv?P=190 Seasonal calendar: https://yle.fi/aihe/tekstitv?P=830 https://yle.fi/aihe/tekstitv?P=830 Museum of Teletex Art: https://yle.fi/aihe/tekstitv?P=805 https://yle.fi/aihe/tekstitv?P=805

cf100clunk 4y ago

For files of captured video containing teletext, there is ccextractor to pull it out: https://ccextractor.org/public/general/whatsccextractor/ https://ccextractor.org/public/general/whatsccextractor/ I've never tried ccextractor for pulling teletext but I use it for pulling almost any kind of closed captions.