diff options
author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-09-13 21:16:04 -0400 |
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committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-09-18 22:47:55 -0400 |
commit | 8e080c2e6cadada82a6b520e0c23a1cb974822d5 (patch) | |
tree | 991450ff1abba98e5313906478c33816a202ccab /Documentation/DocBook/v4l/dev-teletext.xml | |
parent | f4e96deb4513d044653027d4921fd7592195503a (diff) |
V4L/DVB (12761): DocBook: add media API specs
The V4L and DVB API's are there for a long time. however, up to now,
no efforts were done to merge them to kernel DocBook.
This patch adds the current versions of the specs as an unique compendium.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/v4l/dev-teletext.xml')
-rw-r--r-- | Documentation/DocBook/v4l/dev-teletext.xml | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/DocBook/v4l/dev-teletext.xml b/Documentation/DocBook/v4l/dev-teletext.xml new file mode 100644 index 000000000000..59f9993e1489 --- /dev/null +++ b/Documentation/DocBook/v4l/dev-teletext.xml | |||
@@ -0,0 +1,40 @@ | |||
1 | <title>Teletext Interface</title> | ||
2 | |||
3 | <para>This interface aims at devices receiving and demodulating | ||
4 | Teletext data [<xref linkend="ets300706" />, <xref linkend="itu653" />], evaluating the | ||
5 | Teletext packages and storing formatted pages in cache memory. Such | ||
6 | devices are usually implemented as microcontrollers with serial | ||
7 | interface (I<superscript>2</superscript>C) and can be found on older | ||
8 | TV cards, dedicated Teletext decoding cards and home-brew devices | ||
9 | connected to the PC parallel port.</para> | ||
10 | |||
11 | <para>The Teletext API was designed by Martin Buck. It is defined in | ||
12 | the kernel header file <filename>linux/videotext.h</filename>, the | ||
13 | specification is available from <ulink url="http://home.pages.de/~videotext/"> | ||
14 | http://home.pages.de/~videotext/</ulink>. (Videotext is the name of | ||
15 | the German public television Teletext service.) Conventional character | ||
16 | device file names are <filename>/dev/vtx</filename> and | ||
17 | <filename>/dev/vttuner</filename>, with device number 83, 0 and 83, 16 | ||
18 | respectively. A similar interface exists for the Philips SAA5249 | ||
19 | Teletext 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 | ||
23 | with character device file names <filename>/dev/vtx0</filename> to | ||
24 | <filename>/dev/vtx31</filename>, device major number 81, minor numbers | ||
25 | 192 to 223. For reference the V4L Teletext API specification is | ||
26 | reproduced here in full: "Teletext interfaces talk the existing VTX | ||
27 | API." Teletext devices with major number 83 and 102 will be removed in | ||
28 | Linux 2.6.</para> | ||
29 | |||
30 | <para>There are no plans to replace the Teletext API or to integrate | ||
31 | it into V4L2. Please write to the linux-media mailing list: &v4l-ml; | ||
32 | when the need arises.</para> | ||
33 | |||
34 | <!-- | ||
35 | Local Variables: | ||
36 | mode: sgml | ||
37 | sgml-parent-document: "v4l2.sgml" | ||
38 | indent-tabs-mode: nil | ||
39 | End: | ||
40 | --> | ||