[mythtv-users] Deinterlacing Methods

James Buckley xanium4332 at googlemail.com
Sat Jan 13 12:32:11 UTC 2007

Hi all,

Before I ask my question let me list my current setup: (Skip to the bottom
paragraph for the main question)

*MythTV Box (Dual frontend/backend)
Motherboard:* MSI K8NGM2-FID
*CPU:* AMD 3700+
* GFX Card:* nVidia 6150, onboard, with DVI, AGP, Component, & Composite out
*HDD:* 1x SATA 200Gb

*Type: *LCD
*Model: *LG 37LP1D
*Inputs: *DVI (PC), DVI (TV), Componet, HDMI
Working Modelines: 1280x720p, at 50Hz with a little overscan

Basically, I've been working on this box since Easter. I've had lots of
problems, including driver bugs for the graphics card, bios bugs (still
having problems), problems with my VFD & Remote, etc...

My main problem was TV playback. I had my TV set on 'DVI (PC)', and the EDID
information passed let me get a picture with no overscan whatsoever. The
drawback with this was that it was dropping frames (badly, don't know why,
just TV is unwatchable). TV was jerky, (especially the news tickers). I
eventually switched to DVI (TV), but had many problems getting a working
setup (custom modeline, X.org settings etc..). However, with much tinkering
I now have a working display (operating at the above posted modeline). My
problem is deinterlacing:

I've found that I just can't match the quality of TV from my freeview STB.
I've gone through all the deinterlacing methods, and the only one that has a
decent framerate is BOB. However, I find that BOB causes some parts of the
picture to flicker. Normal scenes look fine, but when digital boxes are
drawn on the screen (such as a news ticker), the horizontal edges between
the box and the rest of the picture will flicker slightly. It's a bit hard
to explain, but is most noticeable when a static picture is displayed. The
whole picture isn't jumping (like when there is a refresh rate mismatch),
just objects which are perfectly horizontal flicker (and is bit annoying). I
also oversize the picture slightly to get rid of the top and bottom lines
from flickering

People have told me that you can get perfect TV using Kernel deinterlacing,
with a framerate that's as good as standard TV (and doesn't have any
flicker), however for me this method just doesn't have enough FPS.

I don't know whether my problems are related to an incorrect setup (using
Gentoo), buggy hardware, or just my incompetence, but could someone tell me
what I *should* get from each of the deinterlacing methods, as I've never
had anything to compare too!

Thanks in advance, James

P.S. Sorry for the long post...
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