[mythtv-users] How I got great quality TV-out on my nVidia MX4000
Cory Papenfuss
papenfuss at juneau.me.vt.edu
Thu Mar 10 12:47:04 UTC 2005
> What about RTLinux or RTAI Linux? This would give the realtime performance
> needed to respond to a VBI interrupt, the problem would be that the RTLinux
> code to interract with the graphics card would have to be written from
> scratch. Just a thought, I haven't really been following this thread.
>
I ran across this... looks interesting.
http://www.cs.yorku.ca/~av/Genlock.htm
I've talked myself right out of genlocking with my previous post,
however. Genlocking is a *hard* realtime requirement, whereas since the
PVR is fundamentally a timeshifting device, it's more of a *soft* realtime
device. That's not to say it's not interesting or a possible solution,
it's just that it might be overkill. The easiest way to adjust the time
and keep everything synchronous would be to adjust the dotclock on the VGA
card a very small amount. That would keep the modeline timings the same
on a per-frame basis, but adjust the actual time.
Of course, this is all dependent on the specific video card used,
how adjustable it is, and some notion of a "reference clock." See
previous posts on linux not being realtime... :)
-Cory
*************************************************************************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
*************************************************************************
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