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This is a suite of tools for processing teletext signals recorded on VHS, as
well as tools for processing teletext packet streams. The software has only
been tested with bt8x8 capture hardware, but should work with any VBI capture
hardware if you write a new configuration file (see config_bt8x8_pal.py).
This is a rewrite of the original software using a new CUDA-accelerated
algorithm. It is much faster than the original and also somewhat more
accurate. The old code is still available in the 'v1' branch of this repo.
You can see my collection of pages recovered with this software at:
https://al.robotfuzz.com/~al/teletext/
And more at:
http://www.uniquecodeanddata.co.uk/teletext76/
And:
http://archive.teletextart.co.uk/
INSTALLATION
------------
In order to use CUDA decoding you need to use the Nvidia proprietary driver.
Install python dependencies:
sudo apt-get install python-numpy python-scipy python-pycuda nvidia-modprobe python-enchant
pip install --user scikit-cuda
You can use setup.py to install, or just add the source directory to your
path.
In order for the output to be rendered correctly you need to use a specific
font and terminal:
sudo apt-get install tv-fonts rxvt-unicode
Then enable bitmap fonts in your X server:
cd /etc/fonts/conf.d
sudo rm 70-no-bitmaps.conf
sudo ln -s ../conf.avail/70-yes-bitmaps.conf .
After doing this you may need to reboot.
Finally open a terminal with the required font:
urxvt -fg white -bg black -fn teletext -geometry 41x25 +sb &
USAGE
-----
First capture VBI from VHS:
vbicat /dev/vbi0 > capture.vbi
Scan for headers in the capture:
deconvolve -H -S 20 capture.vbi > headers.txt
Examine the headers to find services on the tape:
less -r headers.txt
Deconvolve a section of the capture corresponding to one service:
deconvolve --start <N> --stop <N> capture.vbi > stream.t42
Display all copies of a page in a stream:
t42pipe stream.t42 -P -p 100
Squash duplicate subpages, which reduces errors:
t42pipe stream.t42 -S > output.t42
Generate HTML pages from a stream:
mkdir output
t42html stream.t42 output
Interactively view the pages in a t42 stream:
t42service stream.t42 | t42interactive
In the interactive viewer you can type page numbers, or '.' for hold.
Run each command with '--help' for a complete list of options.