inear/dvb-tools/util/alevt/README.OLD

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)