4266129964
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>
37 lines
1.6 KiB
XML
37 lines
1.6 KiB
XML
<title>Teletext Interface</title>
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<para>This interface was aimed at devices receiving and demodulating
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Teletext data [<xref linkend="ets300706" />, <xref linkend="itu653" />], evaluating the
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Teletext packages and storing formatted pages in cache memory. Such
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devices are usually implemented as microcontrollers with serial
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interface (I<superscript>2</superscript>C) and could be found on old
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TV cards, dedicated Teletext decoding cards and home-brew devices
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connected to the PC parallel port.</para>
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<para>The Teletext API was designed by Martin Buck. It was defined in
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the kernel header file <filename>linux/videotext.h</filename>, the
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specification is available from <ulink url="ftp://ftp.gwdg.de/pub/linux/misc/videotext/">
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ftp://ftp.gwdg.de/pub/linux/misc/videotext/</ulink>. (Videotext is the name of
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the German public television Teletext service.)</para>
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<para>Eventually the Teletext API was integrated into the V4L API
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with character device file names <filename>/dev/vtx0</filename> to
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<filename>/dev/vtx31</filename>, device major number 81, minor numbers
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192 to 223.</para>
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<para>However, teletext decoders were quickly replaced by more
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generic VBI demodulators and those dedicated teletext decoders no longer exist.
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For many years the vtx devices were still around, even though nobody used
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them. So the decision was made to finally remove support for the Teletext API in
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kernel 2.6.37.</para>
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<para>Modern devices all use the <link linkend="raw-vbi">raw</link> or
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<link linkend="sliced">sliced</link> VBI API.</para>
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<!--
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Local Variables:
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mode: sgml
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sgml-parent-document: "v4l2.sgml"
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indent-tabs-mode: nil
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End:
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-->
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