[vdr] RGB/PAL over VGA at variable frame rate

Thomas Hilber vdr at toh.cx
Thu Jul 24 13:31:13 CEST 2008


On Thu, Jul 24, 2008 at 09:02:50PM +1000, Torgeir Veimo wrote:
> > Hmm.. I still don't understand why you need to do this in the first  
> > place?
> 
> 
> It is to avoid the output framerate drifting away from the DVB-T/S/C  
> input framerate.

right. Normally Xserver modelines can only produce 'discrete' and
'static' video timings somewhere near 50Hz. For example 50.01Hz 
if you are lucky.

With the patch you can dynamically fine tune the frame rate by about
0.000030Hz steps what should be enough for our purpose:)

I actually measured this step size by a quickly hacked measurement
tool (drift_monitor) which can be found here (field_sync_tools.tgz):

http://www.vdr-portal.de/board/thread.php?postid=739784#post739784




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