[vdr] vdpau output to pal tv,

Tony Houghton h at realh.co.uk
Mon Feb 16 22:05:04 CET 2009


On Mon, 16 Feb 2009 21:28:56 +0100
Thomas Hilber <vdr at toh.cx> wrote:

> On Mon, Feb 16, 2009 at 11:48:50PM +1000, Torgeir Veimo wrote:
> > 
> > On 16 Feb 2009, at 23:29, Tony Houghton wrote:
> > 
> > > And if the video has to be scaled it would have to scale each field
> > > separately then reinterlace them line-by-line at the output resolution
> 
> @Tony Houghton:
> is it really possible to scale each field separately without producing
> artifacts? Isn't deinterlacing always neccessary prior to scaling? 
> IMHO scaling does imply that even lines are allowed to blur into odd lines
> if the scale factor forces this.
> 
> But artifact free blur of both fields is NOT possible if you either 
> - don't deinterlace prior to scale
> or
> - keep even and odd fields separated during scale

You're right. I was thinking of cases where there's a lot of movement
and the fields are from different pictures, forgetting that they can
alternatively add detail to static scenes.

> > Ok, I guess this single issue implies that vdpau is not fully suitable  
> > for displaying interlaced material with interlaced output.
> 
> @Torgeir Veimo:
> not sure about this. Intel series i9xx graphics is able to scale by
> hardware even in interlaced mode. I use this feature for my intel based
> frame rate control patches (SCART/RGB/PAL vga-sync-fields patch).

VDPAU is currently only on NVidia cards although it's possible Intel and
even ATI may provide backends for it in the future. I think only the
most recent Intel chipsets support H.264 decoding, does your patch work
with those? Once there's a stable API for their H.264 decoding I guess
we'll have the best of both worlds :-).

-- 
TH * http://www.realh.co.uk



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