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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 12:03:10 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 12:03:10 -0400
commitc720f5655df159a630fa0290a0bd67c93e92b0bf (patch)
tree940d139d0ec1ff5201efddef6cc663166a8a2df3 /Documentation/DocBook/v4l/dev-teletext.xml
parent33e6c1a0de818d3698cdab27c42915661011319d (diff)
parent84d6ae431f315e8973aac3c3fe1d550fc9240ef3 (diff)
Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (222 commits) V4L/DVB (13033): pt1: Don't use a deprecated DMA_BIT_MASK macro V4L/DVB (13029): radio-si4713: remove #include <linux/version.h> V4L/DVB (13027): go7007: convert printks to v4l2_info V4L/DVB (13026): s2250-board: Implement brightness and contrast controls V4L/DVB (13025): s2250-board: Fix memory leaks V4L/DVB (13024): go7007: Implement vidioc_g_std and vidioc_querystd V4L/DVB (13023): go7007: Merge struct gofh and go declarations V4L/DVB (13022): go7007: Fix mpeg controls V4L/DVB (13021): go7007: Fix whitespace and line lengths V4L/DVB (13020): go7007: Updates to Kconfig and Makefile V4L/DVB (13019): video: initial support for ADV7180 V4L/DVB (13018): kzalloc failure ignored in au8522_probe() V4L/DVB (13017): gspca: kmalloc failure ignored in sd_start() V4L/DVB (13016): kmalloc failure ignored in lgdt3304_attach() and s921_attach() V4L/DVB (13015): kmalloc failure ignored in m920x_firmware_download() V4L/DVB (13014): Add support for Compro VideoMate E800 (DVB-T part only) V4L/DVB (13013): FM TX: si4713: Kconfig: Fixed two typos. V4L/DVB (13012): uvc: introduce missing kfree V4L/DVB (13011): Change tuner type of BeholdTV cards V4L/DVB (13009): gspca - stv06xx-hdcs: Reduce exposure range ...
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1 <title>Teletext Interface</title>
2
3 <para>This interface aims at devices receiving and demodulating
4Teletext data [<xref linkend="ets300706" />, <xref linkend="itu653" />], evaluating the
5Teletext packages and storing formatted pages in cache memory. Such
6devices are usually implemented as microcontrollers with serial
7interface (I<superscript>2</superscript>C) and can be found on older
8TV cards, dedicated Teletext decoding cards and home-brew devices
9connected to the PC parallel port.</para>
10
11 <para>The Teletext API was designed by Martin Buck. It is defined in
12the kernel header file <filename>linux/videotext.h</filename>, the
13specification is available from <ulink url="ftp://ftp.gwdg.de/pub/linux/misc/videotext/">
14ftp://ftp.gwdg.de/pub/linux/misc/videotext/</ulink>. (Videotext is the name of
15the German public television Teletext service.) Conventional character
16device file names are <filename>/dev/vtx</filename> and
17<filename>/dev/vttuner</filename>, with device number 83, 0 and 83, 16
18respectively. A similar interface exists for the Philips SAA5249
19Teletext decoder [specification?] with character device file names
20<filename>/dev/tlkN</filename>, device number 102, N.</para>
21
22 <para>Eventually the Teletext API was integrated into the V4L API
23with character device file names <filename>/dev/vtx0</filename> to
24<filename>/dev/vtx31</filename>, device major number 81, minor numbers
25192 to 223. For reference the V4L Teletext API specification is
26reproduced here in full: "Teletext interfaces talk the existing VTX
27API." Teletext devices with major number 83 and 102 will be removed in
28Linux 2.6.</para>
29
30 <para>There are no plans to replace the Teletext API or to integrate
31it into V4L2. Please write to the linux-media mailing list: &v4l-ml;
32when the need arises.</para>
33
34 <!--
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