Teletext separated mosaic graphics

Kent Karlsson kent.b.karlsson at
Sat Oct 10 17:02:35 CDT 2020

Here are a few more web sites showing Teletext pages from various European TV channels.
THE LIST IS SURELY FAR FROM COMPLETE, it is just a sample. But it does show that Teletext
is commonly displayed as web pages, not just via TV channels (whether "analog" or DVB).
I haven't seen these combined with web versions of TV channels, but that would surely
be possible to combine. That would be especially useful for optional subtilting, where
Teletext is still much used, as a useful accessibility feature.
I have no prediction of how long any channels will continue to produce Teletext content.
But optional subtilting seems to "survive" longer.
I do not know what source format(s) may be used, but it is surely not HTML *nor* close
to the Teletext protocol. But see the Teletext page edit tool referenced below.
Spain, RTVE: <>
Sweden, SVT: <> (also as iOS app, same name) <>
Iceland, RÚV: <>
Denmark, DR: <>
Norway, NRK: <>
Finland, YLE: <>
Switzerland, SRF: <>
Croatia, HRT: <>
Greece: <>
And more; I have not done a complete survey!
There are also several apps for iOS and for Android that display Teletext content from
various (TV channel) providers.
What the source format is for the Teletext pages as produced today, I don't know. But I would
guess that it is likely "plain text" files, with Teletext specific markup, that is then converted to
1) Teletext analog format, 2) Teletext DVB format, 3) HTML. But that is just my guess.
Again note that Teletext is still commonly used for optional subtitles. (DVB subtitles, a "bitmapped"
format (i.e. the subtitles are sent as images, not text) does not seem to be used much. At least, I
haven't seen it.) This requires timing, which is not part of the Teletext protocol, but must be in
the source in order to control when a subtitle is output as Teletext for optional display.
   "But a teletext application for a modern computer is not "normal use." It is reasonable
   for a non-standard application like this to interpret characters from U+0000 to U+001F
   as the corresponding ISO 646 characters would be in teletext."
is very false.
Further, the "object" overrides in the Teletext *protocol*, in several levels, "objects"
prioritized depending on "implementation level", can specify:
1) Bold, italic, underline, proportional font.
2) More colours (but only 16 levels per red/green/blue, no transparency though).
3) Character substitutions (likely replacing spaces) to be able to display characters from "G3".
These cannot be handled by "retaining" the ill-designed control codes of Teletext anyway.

Have an urge to edit your own Teletext pages? Here’s the web page for doing just that:

You can save your page in a handful of formats (plus as image). I haven’t analyzed these formats,
but presumably they are storage formats actually used for ”real” Teletext pages that are converted
to be transmitted (”analog” (outdated) or DVB) or given as web pages (HTML, but no ”separated
mosaic” characters, since they are not yet allocated in Unicode; could use small images though...).

/Kent K

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