Re: [V4L] vbi

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> > It would be nice to see some provision for handling the type of
> > video data.  For example, most analog video decoders can do
> > either raw VBI or sliced (teletext, CC, etc.).  If there *is* a way to
> > specify this, I would like to know.
> > 
> >     -- Peter
> 
> You can have a look at the v4l2 vbi spec available from
> http://www.thedirks.org/v4l2 . This is the api that seems (from the
> header files at least), to be used in the new kernel series.  It also
> explains how to get what data from the driver (ie. raw vbi, or just
> teletext/cc).

Yes, I used this document when planning my driver.  BTW, I wrote
a V4L2 driver for the Geode processor.  We use a Philips SAA7114,
which can slice CC data or pass along raw VBI data.  Unfortunately,
the spec does not appear to have a flag in the set format IOCTL to
specify how the user wants to receive the data.  My temporary hack is
to say if the user wants 2 bytes per line, then give them sliced CC.
This is not a good solution for many reasons.  But, it works.

Because the processor captures VBI data (and video) to system 
memory, the mmap() call turns out to be really nice.  The driver provides
this alternative so the user may do what it wishes with the data.

Thanks,

    Peter






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