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

[Craig Longman]

Will Dormann wrote:

>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.
>
is this outputting to a tv or a monitor?

>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/
>
i also get interlacing problems.  i'm in the middle of trying to track 
it down.  i had stopped using mythtv for live tv as the picture looked 
so much crappier than the real tv signal.  i initially had figured that 
my tv had a significantly better tuner/filtering system than the pvr250 
does, and being uncompressed and all was just producing a better 
picture.  however, while playing around with the nvtv app (i have an 
nvidia geforce card) i noticed the 'Flicker' option.  it had been set 
high, and was producing a very fuzzy, out-of-focus sort of picture. 
 setting this to a lower number improved the clarity substantially.  i 
eventually settled on '40' as a good mix between not having pure 
horizontal lines flicker and good clarity, but then the motion artifacts 
started getting real bad.  it seems like the 'Flicker' setting just sort 
of blurs things until there are no more single ntsc-lines of 
information, then the 'flicker' goes away, of course.

>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.
>
well, not just sis.

>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 interested in hearing someone who knows whats going on answer here.

>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?
>
i don't think you CAN deinterlace the pvr250 output with myth.  all the 
deinterlacing code is in the NuppleVideoRecorder, which i don't think is 
used for writing the hardware encoded streams, but i'm not positive here.

i had been planing on quickly trying to get the avcodec library to 
deinterlace the video while decoding it to see if it helped.  depending 
on what this thread turns up, i may forget about that, or get on it 
immediately.  those jumping lines/honeycombs at the edges are quite 
distracting.

cheers,

    CraigL->Thx();