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Subject[ANNOUNCE] new driver for teletext decoder SAA5246A
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Hello,

I would like to introduce a new device driver for the I2C based
Videotext/Teletext decoder SAA5246A from Philips. The interface
is identical to the existing driver for the SAA5249 chip. User
programs can access these devices via /dev/vtx0 ... /dev/vtx31.

Templete was drivers/media/video/saa5249.c, some of the SAA5246A
functionality was taken from the original driver from Martin Buck
(http://home.pages.de/~videotext/). In order to make the driver
sources easier to understand I added lots of symbolic constants
related to the data sheet of the SAA5246A from Philips.

The driver is available as a patch to the linux kernel version
2.6.3 from http://www.michaelgeng.de/linux/saa5246a-2.6.3.patch

I know that today's TV cards do no more have such a teletext
processor chip on board, they use the CPU for decoding videotext
pages. This is much faster if you want to extract all the pages
from a TV station for reading like a journal. I also wanted to
change to the vbi interface but after some trial I went back to
decoding via SAA5246A because there were more errors in the pages
decoded with the vbi interface than with the vtx interface using
a SAA5246A. I don't know why. And have you tried to capture a
special subpage from a page that contains 10 suppages or more?
When it is finally transmitted after 10 Minutes you will have to
wait for another 10 Minutes if your CPU missed it. According to my
experience a teletext processor will more probably capture the
page.

Of courde I have tested the driver both as a module and compiled
into the kernel. It is licensed under the GPL.

I would be happy to get some feedback!

Michael

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