>
> > Strictly speaking, you get a "1/2 pixel" flickering, not 1 pixel.
> I don't understand the 1/2 pixel notation, what I see is about 70 pizels
> that are quite black (with some noise)
>
When watching consecutive fields, images seem to be down-displaced for
odd fields. This displacement is not one-pixel sized, but what I call
"1/2" pixel, since the digitalised samples correspond to those "just in
between upper and lower lines from the even field". See:
EVEN ODD EVEN ODD ...
xxxxxx xxxxxx } This is what I call
bbbxxx bbbxxx } 1/2 pixel displacement
xxxxxx xxxxxx
xxxxxx xxxxxx } This is what I call
xxxxxx xxxxxx } 1 pixel
xxxxxx xxxxxx } displacement
xxxbbb xxxbbb
xxxxxx xxxxxx
> we added a LM1881
> > (a sync detector) chip in our board design and wired its ODD/#EVEN
> > output directly to one of the GPIO pins. This HW info IS reliable.
>
> what is LM1881 and how does IT know what is even and what is odd?
Google search: LM1881 ;-)
http://www.national.com/pf/LM/LM1881.html
>
> > What we do is take any parity and if frames are odd, mark them at
> > interrupt time and interpolate (linear algorithm, just the mean of both
> > upper and lower pixels) them so that they "ressemble" even ones.
> >
> great tip, but it heavily depends on distinguishing even/odd frames, so the
> previos question...
>
Yes. it does. However, info from LM1881 has turned out to be fully
reliable for us.
Bye,
Miguel
