[mythtv-users] Asus Pundit and Interlaced Output, part III :)

[Will Dormann]

Ok, I've done further research into this issue...

My PVR-250 is capturing interlaced video fine.
I've checked one such captured video on my Windows PC
and it looks fine.  It looks OK normally, and by
deinterlacing it into side-by-side fields it looks
great.  There are no distortions in the video at all.

Now, when I play that very same video with mplayer on
my MythTV box I get interlacing problems.   It looks
very close to the first screenshot here, where there
are scenes with fast motion:
http://www.100fps.com/

So I think I've narrowed down the problem to my X
configuration with the SIS chip on my Pundit.  Unless
I'm totally misunderstanding how interlaced output to
a TV should look, I don't think I should be seeing
these disortions.

A good way to see the distortion is to pause a scene
with fast motion.   I'm seeing a combination of two
things.  First, there are wavy edges on the objects,
like that first screenshot from 100fps.com.  But I'm
also seeing seeing some "comb" edges like from the
second screenshot there.

Now, I've always been under the impression that you
*always* want to output interlaced video if the
destination device is a TV.   Interlaced video will
give smoother motion due to it being nearly 60 fields
per second.   While progressive is nearly 30 frames
per second.    So when two fields are drawn on the TV,
a progressive source will draw the same deinterlaced
frame twice, but an interlaced source will display the
two consecutive (and slightly different) fields.

I'm applying my knowledge of VCD vs. SVCD/DVD here.  
Does the same thing apply with a computer that has TV
out functionality?    If I enable deinterlacing in the
mythtv prefs, it does make the picture look a lot
nicer, especially when paused.    Am I wasting my time
trying to get interlaced (or non-deinterlaced, if you
like the double negatives) video working right?

thanks!
-WD

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