[mythtv] Ideas for high quality TV-out

Michael Wright mikewright at iprimus.com.au
Mon Jun 28 11:20:41 EDT 2004

Hi Ed,

I think the type of de-interlace I want to do is called "Bob
de-interlace".  This method basically takes the 25 FPS video and turns
the odd and even fields in a frame into 2 separate frames. These 2 are
then played back at 50 FPS.  Does the Kerneldeint filter do that?  I'll
try reading up anyway.

I don't believe the ability to display interlaced content correctly via
Nvidia TV-out is actually a function of the driver.  When TV-out is
enabled (via nv-tv-out), the card is programmed for 50Hz operation.  The
Chrontel TV encoder generates PAL fields on the fly I believe.  So I'm
guessing that if you display 50 FPS video while it is programmed for 50
Hz operation the TV will get each field correctly.  I.e. each frame of
the 50 FPS video will map directly to a PAL field.


On Mon, 2004-06-28 at 15:36, Ed Wildgoose wrote:
> >>Any ideas on how to do this?
> >>    
> >>
> >
> >It's all been done in tvtime (tvtime.sf.net) already. Looks very nice and has 
> >neat field order detection etc. Too bad it takes an insane amount of cpu: On 
> >my athlon-xp 2000+ around 60% with 768x576 frames, couple that with what cpu 
> >is required to decode the mpeg2+audio.
> >  
> >
> Kerneldeint has already been integrated with Myth.  This is one of the 
> better deinterlacers around - better than the built in one for example.  
> Read up on the "filter manager" for how to enable it.
> There are also already hooks to do a lot of clever filtering in Myth, 
> for example I would be interested in a higher quality resizing 
> algorithm.  This would significantly boost sharpness, and most of the 
> hooks have already been added to do even this
> If you want to do non-interlaced playback though then you are going to 
> have to dig a little.  There is some support added recently for the via 
> decoder, but I think nvidia lacks interlaced output modes on most of 
> it's drivers...
> Ed W
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