Hi, Menden, 21 Sep 2000
This program decodes and displays Videotext/Teletext from a
/dev/vbi device.
COMPILE & INSTALL:
There's nothing to configure. A simple 'make' is all.
If you do not want png support remove the WITH_PNG in
the Makefile. Additionally, if you want a smaller font
uncomment the "FONT=neep9" line.
It gives you 'alevt', 'alevt-date', and 'alevt-cap' and
their man pages 'alevt.1x', 'alevt-date.1', and 'alevt-cap.1'.
You can install them where ever you want (i.e. /usr/local/bin).
The programs are self-contained and require no other files.
NOTE: Be careful with 'make install'. It's just for me :-)
PROBLEMS:
If you have a lot of decoding errors (lot of these lightning symbols)
you may try pressing the 'f' and 'F' key. This allows fine tuning of
the decoder circuit. There's also a -finetune command line option.
This should only be necessary on really bad signals.
Maybe, I add autotuning later...
UPDATE: added autotuning. It's the default. If you add -debug the
the actions of the pll are printed to stdout.
To get the old (pre finetune) behaviour start it with -finetune 0.
UPDATE: disabled autotuning *g* sometimes it's too jumpy...
ALEVT-DATE:
I added a little tool to set the system time from the videotext
time. The date is not interpreted (not even transmitted on some
channels). So it allows only adjustment of +/-12 hours.
The default allowed adjustment is limited to +/-2 hours (use
-delta to change). Without the -set option it just display
the date in the format of the date command. Look at strftime(3)
for possible control sequences you may use in the -format option.
HACKING:
If you want to play with the font size, you may resize it with
xv (xv font1.xbm). Just make sure, that its width is a multiple of
32 and its height a multiple of 8. A simple make will create
a version of AleTV with the new font. Warning: a make clean
will erase font1.xbm. The next make will recreate font.xbm from
vtxt.bdf.
AleVT has a built in page editor. If you start it with -editor
you may press 'E' to invoke it. For the usage you have to consult
the sources. (It's very crude!)
TODO: (no specific order)
- Error correction in alevt-cap
- Better language support. Internal 16-bit charset.
- Separated graphics.
- Rewrite the whole stuff. A networked teletext daemon and clients
that connect to it for display, capture, cgi, ...
NEWER VERSIONS:
The primary site of AleVT is http://goron.de/~froese
Have fun,
Edgar Toernig (froese@gmx.de)
