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https://github.com/tomzox/python-zvbi

Python module providing an object-oriented interface to the ZVBI library (teletext & closed caption decoding)
https://github.com/tomzox/python-zvbi

c capi closed-captions demuxer dvb python-extension python3 teletext v4l2 vbi videotext zvbi-library

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Python module providing an object-oriented interface to the ZVBI library (teletext & closed caption decoding)

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README 

        
# ZVBI library interface module for Python



This repository contains the sources of the "Zvbi" module for Python,

which has its official home at [PyPi](https://pypi.org/project/Zvbi/).

This module is equivalent to the

[Video::ZVBI module for Perl](https://metacpan.org/pod/Video::ZVBI).



This C extension module provides an object-oriented interface to the

[ZVBI library](http://zapping.sourceforge.net/ZVBI/index.html).

The ZVBI library allows accessing television broadcast data services such

as teletext and closed captions via analog or DVB video capture devices.



Official ZVBI library description:



> The ZVBI library provides routines to access raw VBI sampling devices

> (currently the Linux DVB & V4L2 APIs and the FreeBSD, OpenBSD,

> NetBSD and BSDi bktr driver API are supported), a versatile raw VBI

> bit slicer, decoders for various data services and basic search, render

> and export functions for text pages. The library was written for the

> Zapping TV viewer and Zapzilla Teletext browser.



The Zvbi Python module covers all exported libzvbi interfaces.



The Python interface module is largely based on objects which encapsulate

the native C structures of libzvbi. Only when a Python script actually

wants to manipulate captured or decoded data directly (i.e. not via

library functions), the structures' data is converted into Python data

types. Even then, Python methods such as the "buffer protocol" are used to

avoid unnecessary copying. This approach allows for a pretty snappy

performance despite the additional interface layer.



Best starting point to get familiar with the module is having a look at

the *Class Hierarchy*, description of the main classes in the

Python API documentation,

and the example scripts provided in the

examples/ sub-directory, which

demonstrate use of all the main classes.

(The examples are a more or less direct C to Python ports of the respective

programs in the `test/` sub-directory of the libzvbi source tree, plus a

few additions, such as a teletext level 2.5 browser implemented in apx.

300 lines of [Python Tkinter](https://docs.python.org/3/library/tk.html).)

A description of all example scripts can be found in the API documentation

in section "Examples". Additionally you can look at the

[ZVBI home](http://zapping.sourceforge.net/ZVBI/index.html) and the

ZVBI library documentation (unfortunately not available online; built via

doxygen when compiling the library).



## Module information



Module summary:



* development stage python interface: beta release

* development stage libzvbi: mature

* C compiler required for installation

* support of python interface: by developer

* support of libzvbi: no longer maintained (last release 2013)

* object oriented interface

* licensed under GPL-v2 (GNU General Public License, version 2)



Supported operating systems (as determined by ZVBI library):



* Linux

* FreeBSD

* NetBSD

* OpenBSD



## Installation



Pre-requisite to the installation is a C compiler and (obviously) the

[libzvbi library](http://zapping.sourceforge.net/ZVBI/index.html)

(oldest supported version is 0.2.26) which in turn requires the

pthreads and PNG libraries. Once you have installed these,

the module can be installed in the usual steps:



```console

    cd Video-ZVBI

    python3 setup.py test

    python3 setup.py install

```



Note there are no dependencies on other Python extension modules by the

module itself. Some of the provided example scripts however depend on

[Python Tkinter](https://docs.python.org/3/library/tk.html).



## Bug reports



Please submit bug reports relating to the interface module via email

to the author (address listed in module meta data).



If your bug report or request relates to libzvbi rather than the

interface module, please contact the libzvbi authors, preferably

via the [Zapping](http://zapping.sourceforge.net/) mailing list.

In case of capture problems, please make sure to specify which

operating system and hardware you are using, and of course which

version of libzvbi and which version of Python and the ZVBI module

respectively.



## Documentation



For further information please refer to the following files:



* ZVBI.rst: API documentation

* Changelog: Release history & change-log

* README: same content as on this page

* COPYING: GPL-v2 license



## Copyright



Copyright (C) 2006-2020 T. Zoerner.



This program is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 2 of the License, or

(at your option) any later version.



This program is distributed in the hope that it will be useful,

but without any warranty; without even the implied warranty of

merchantability or fitness for a particular purpose.  See the

GNU General Public License for more details.