On Mon, 29 Dec 2008 09:55:45 +0200
"Theunis Potgieter" <theunis.potgie...@gmail.com> wrote:

> deinterlacing is only required if your source/stream runs at a
> different refresh rate than your output monitor. The problem with
> nvidia and the tv-out adapter(s-video plug) is that they decided to
> lock their driver(closed source) to 60Hz after a certain version, for
> newer cards and your output happens to be a CRT screen/monitor. PAL,
> happens to run mostly on 50Hz. You would see tearing and/or the
> individual fields if you do not enable a deinterlacer, which requires
> more cpu load. Offloading it to the gpu could help. The best would be
> to get your output device to run at the same refresh rate. Now there
> are different kinds of approaches: playing with your xorg.conf, to
> disable EDID of the video driver and you define a mode that tells your
> video driver you want 50Hz on your LCD, CRT/Plasma or on ATI there is
> a RGB(red, green, blue) patch, that requires you to plug in an adapter
> cable/board from your vga plug to your output monitor. Look for "PCI
> fun (RGB/PAL over VGA at variable frame rate)" in the mailing list. So
> there is another trick of saving on your electricity bill.

When I had a CRT TV I solved the problem by using a Matrox G400 graphics
card with vdr-fbfe. With a monitor or LCD TV I think there's still a
deinterlacing problem even if you can sync the refresh rates. This
didn't work on CRTs either with ordinary graphics cards (other than the
Matrox and things like FF cards specialised for TVs) because there was
no way for player applications to distinguish between top and bottom
fields in the vblank interrupts. Matching refresh rates alone doesn't
help very much; by scaling each field to the full size of the screen
you're just performing "bob" deinterlacing which may not look very good
compared to somehow interpolating data across fields, especially if that
could be done intelligently with motion vectors from the MPEG data.

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

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