Commit 0b7a4b41 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab

media: dev-teletext.rst: remove obsolete teletext interface

The teletext interface has been dead for years now, just
remove it.
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent b4ba92d5
.. Permission is granted to copy, distribute and/or modify this
.. document under the terms of the GNU Free Documentation License,
.. Version 1.1 or any later version published by the Free Software
.. Foundation, with no Invariant Sections, no Front-Cover Texts
.. and no Back-Cover Texts. A copy of the license is included at
.. Documentation/media/uapi/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
.. _ttx:
******************
Teletext Interface
******************
This interface was aimed at devices receiving and demodulating Teletext
data [:ref:`ets300706`, :ref:`itu653`], evaluating the Teletext
packages and storing formatted pages in cache memory. Such devices are
usually implemented as microcontrollers with serial interface
(I\ :sup:`2`\ C) and could be found on old TV cards, dedicated Teletext
decoding cards and home-brew devices connected to the PC parallel port.
The Teletext API was designed by Martin Buck. It was defined in the
kernel header file ``linux/videotext.h``, the specification is available
from
`ftp://ftp.gwdg.de/pub/linux/misc/videotext/ <ftp://ftp.gwdg.de/pub/linux/misc/videotext/>`__.
(Videotext is the name of the German public television Teletext
service.)
Eventually the Teletext API was integrated into the V4L API with
character device file names ``/dev/vtx0`` to ``/dev/vtx31``, device
major number 81, minor numbers 192 to 223.
However, teletext decoders were quickly replaced by more generic VBI
demodulators and those dedicated teletext decoders no longer exist. For
many years the vtx devices were still around, even though nobody used
them. So the decision was made to finally remove support for the
Teletext API in kernel 2.6.37.
Modern devices all use the :ref:`raw <raw-vbi>` or
:ref:`sliced` VBI API.
...@@ -24,7 +24,6 @@ Interfaces ...@@ -24,7 +24,6 @@ Interfaces
dev-codec dev-codec
dev-raw-vbi dev-raw-vbi
dev-sliced-vbi dev-sliced-vbi
dev-teletext
dev-radio dev-radio
dev-rds dev-rds
dev-sdr dev-sdr
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment