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

Torgeir Veimo torgeir at pobox.com
Wed Jul 23 10:04:29 CEST 2008

On 23 Jul 2008, at 02:37, Thomas Hilber wrote:

> To a certain degree you can workaround this by software deinterlacing.

> After some further experimenting I finally found a solution to fine  
> adjust the
> frame rate of my elderly Radeon type card.

> Just trimming the length of a few scanlines during vertical retrace
> period does the trick.
> Then I tried to implement the new functionality by applying only  
> minimum
> changes to my current VDR development system. Radeon DRM driver is  
> perfectly
> suited for that.

> I finally ended up in a small patch against Radeon DRM driver and a  
> even
> smaller one against xine-lib.

Your approach is very interesting, I myself have seen the problems  
that clock drift has on judder when using softdevice with vdr.

Have you considered applying your approach to DirectFB? There's a  
radeon driver which is not too hard to change, it also has a kernel  
module which could be augmented by using an ioctl command.

In addition, you might want to try out your approach with a matrox  
G550 card. These have field perfect interlaced output using DirectFB,  
so you'd have that part of the problem solved already.

Torgeir Veimo
torgeir at pobox.com

More information about the vdr mailing list