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author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-05-31 16:27:44 -0300 |
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committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-07-27 17:52:05 -0300 |
commit | 4266129964b8238526936d723de65b419d8069c6 (patch) | |
tree | 38c6b5cd3dc99b8599391ffad3b87e399bef56a2 /Documentation/DocBook/media/v4l/dev-teletext.xml | |
parent | 04893043ae9ea8aa82b712491ed25ba6c4ffbca3 (diff) | |
download | op-kernel-dev-4266129964b8238526936d723de65b419d8069c6.zip op-kernel-dev-4266129964b8238526936d723de65b419d8069c6.tar.gz |
[media] DocBook: Move all media docbook stuff into its own directory
This patch addresses several issues pointed by Randy Dunlap
<rdunlap@xenotime.net> at changeset ece722c:
- In the generated index.html file, "media" is listed first, but it
should be listed in alphabetical order, not first.
- The generated files are (hidden) in .tmpmedia/
- The link from the top-level index.html file to "media" is to
media/index.html, but the file is actually in .tmpmedia/media/index.html
- Please build docs with and without using "O=builddir" and test that.
- Would it be possible for media to have its own Makefile instead of
merging into this one?
Due to the way cleandocs target works, I had to rename the media DocBook
to media_api, otherwise cleandocs would remove the /media directory.
Thanks-to: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/dev-teletext.xml')
-rw-r--r-- | Documentation/DocBook/media/v4l/dev-teletext.xml | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/dev-teletext.xml b/Documentation/DocBook/media/v4l/dev-teletext.xml new file mode 100644 index 0000000..414b1cf --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-teletext.xml @@ -0,0 +1,37 @@ + <title>Teletext Interface</title> + + <para>This interface was aimed at devices receiving and demodulating +Teletext data [<xref linkend="ets300706" />, <xref linkend="itu653" />], evaluating the +Teletext packages and storing formatted pages in cache memory. Such +devices are usually implemented as microcontrollers with serial +interface (I<superscript>2</superscript>C) and could be found on old +TV cards, dedicated Teletext decoding cards and home-brew devices +connected to the PC parallel port.</para> + + <para>The Teletext API was designed by Martin Buck. It was defined in +the kernel header file <filename>linux/videotext.h</filename>, the +specification is available from <ulink url="ftp://ftp.gwdg.de/pub/linux/misc/videotext/"> +ftp://ftp.gwdg.de/pub/linux/misc/videotext/</ulink>. (Videotext is the name of +the German public television Teletext service.)</para> + + <para>Eventually the Teletext API was integrated into the V4L API +with character device file names <filename>/dev/vtx0</filename> to +<filename>/dev/vtx31</filename>, device major number 81, minor numbers +192 to 223.</para> + + <para>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.</para> + + <para>Modern devices all use the <link linkend="raw-vbi">raw</link> or +<link linkend="sliced">sliced</link> VBI API.</para> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> |