[mythtv] Kernel 2X HW-GL Deinterlacing

Peter Bennett pb.mythtv at gmail.com
Sat Nov 24 22:25:30 UTC 2018

On 11/24/18 12:42 PM, David Engel wrote:
> The effect I see on my Shields when reversed is not selected is very
> much like a non-deinterlaced image -- the alternating scan lines are
> offset by a few pixels.  It's most apparent on scrolling news tickers.
> When reversed is selected, the scan lines all line up nicely.  Have
> you tried it on your Shield?
> What's troubling is the inconsistency.  Mark's comment about the
> coordinates being different between OpenGL and OpenGLES could explain
> why the Shield needs reversed selected to look good.  If that was
> true, though, I'd expect selecting reversed to look bad on Linux but
> it doesn't.
I tried it on my shield, with standard decode and opengl  display - 
using HW-GL deinterlacers -
Kernel 2x - the ticker looks double, two flickering copies of it 
scrolling - most unpleasant.
Kernel 2x with interlace reversed selected - perfect.
Kernel 1x - the ticker shakes while scrolling.
Kernel 1x with interlace reversed selected - smoother, almost perfect.
Linear Blend 2x - perfect
Linear Blend 2x with interlaced reversed selected - the ticker looks 
double, two flickering copies of it scrolling - most unpleasant.
Linear Blend 1x - ticker shakes while scrolling
Linear Blend 1x with interlaced reversed - same as with interlaced 
normal - ticker shakes while scrolling

In 2x deinterlace, Linear blend and kernel seem equal, except that 
kernel gets it wrong by needing the interlace reversed.
in 1x deinterlace, kernel is better but gets it wrong by needing 
interlace reversed.

I am afraid I cannot offer any hope as far as understanding the OpenGL 
is concerned, it seems to be a very complicated subject.


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