/vhs-teletext

Software to recover teletext data from VHS recordings.
  1. Python 98.3%
  2. CSS 1.7%
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Latest commit a9b174c Jan 4, 2018 @ali1234 ali1234 Don't append extra debug information when turning headers to ANSI. 
This messes up the interactive viewer.
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misc More CSS tweaks. Mar 26, 2016
teletext Don't append extra debug information when turning headers to ANSI. Jan 4, 2018
.gitignore Ignore some build products May 24, 2016
HOW_IT_WORKS Remove some outdated bits. Nov 30, 2017
README Add link to teletext archives Jul 23, 2017
TRAINING.md Add some docs about training. Sep 12, 2016
config_bt8x8_pal.py Fix warning about array indices. Apr 26, 2017
config_saa7131_secam.py [config] Add config file for SAA7131. Aug 4, 2017
deconvolve Update deconvolve and line.py for the new Packet API. Mar 21, 2016
setup.py Add more scripts to setup.py May 24, 2016
t42example Add an example showing how to use Service when generating pages. Mar 21, 2016
t42html [t42html] Add alternative style sheet definition for no scanlines. Aug 4, 2017
t42interactive Don't append extra debug information when turning headers to ANSI. Jan 4, 2018
t42pipe Add args for new functions. May 24, 2016
t42service Add t42service and t42interactive Mar 19, 2016
training Drop a bit from the parity patterns. Feb 28, 2016
vbicat Add vbicat. Feb 21, 2016
vbiview [vbiview] Add more command line options. Aug 4, 2017

README 

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.