[EMAIL PROTECTED] ([EMAIL PROTECTED]):

> >   If we had the vsync as an interrupt (/dev/vsync or something),
> > then quality would increase with less system load!  Very nice!
> > But SCHED_FIFO would still be needed to guarentee accurate blits.
> 
> The other approach is to have a device which you mmap and write your
> frames into. Then you issue an ioctl and the driver DMAs the buffers
> at the next available opportunity. 

  Yes, you could make a cool API to solve the issue.  It would be really
neat.  My only concern would be the difficulty of implementing it with
consumer video cards.  Ideally I'd want 'here's a frame, blit at time X'
and hope that someone in the kernel has an accurate clock.  It would
also need to tell me the (exact) refresh rate + sync point.

> >   Check out deinterlace.sf.net (aka dscaler.sf.net).  [...]
> 
> How big are the cpu requirements ? This is something that is quite
> useful, because, at the moment, v4l does not allow to convey such
> information as field parity..

  Not sure yet.  For v4l, I assume all frames are top-field-first.  v4l2
provides field parity information, and I'm getting flamed on the
video4linux list to switch to it.

> One thing - did you try your dvd player with recent ATI drivers ? ATI
> can doublebuffer frames switching them automatically on vsync. If you
> still see the issue you are worried about something is wrong with our
> drivers - I'd appreciate a lot if you could write a test up to debug
> the issue. (or a test mpeg stream)

  I'm not worried about tearing, I'm worried about amortizing frame
time over the refresh rate in a pleasing way (especially for special
refresh rates like 72hz: think projector).

-- 
Billy Biggs
[EMAIL PROTECTED]
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