Pal DVD’s with blended fields

[nig103]

Hi
I have a problem with pal dvd’s that have blended fields. I’ve done a fair bit of searching the forums but still can’t find a quick fix.

The problem is that with some dvd’s (so far I’ve encountered Conan, Casino and The Shining) I end up with an encoded file that has some good scenes and some scenes with blended fields. By blended fields I mean that it’s like 2 frames are merged and it produces a major ghosting effect during playback. Some movies, like Conan for example play fine for 10 minutes, then swap over to the blended fields for maybe 20 minutes, then back to fine and then back to blended and so on so fourth. I think Conan swapped back and fourth 8 times throughout the whole movie. But some movies like Casino swap back and fourth really regularly.

I’ve played around a fair bit with it and if in your DVD2avi project you select “Swapped field order” under Field ops then you end with a file that is a direct opposite of if you’d selected “ None” in Field ops in your DVD2avi project. By a direct opposite I mean that the scenes that were bad in the “field ops:swapped” file with be good in the “field ops:none” file and vice versa. I’ve attached a couple of screenshots from Casino as an example of this. So by doing this you can (if you can be bothered) go through and manually work out where it changes from being good to bad, make a note of the frame numbers, create 2 separate .avs files (1 with “field ops=none” and the other with “field ops=swapped”) and encode all the good bits manually. Then join them up and it’s all good. I did this for Conan as it didn’t change that regualarly. Didn’t take that long, longest part was working out the frames where it’d change. But if you tried to do casino like that it would take forever. So my question is if anybody knows of a better way of doing this?

Another thing is that when you playback these DVD’s in the PC you get the blended frames playback problems as well. However I just bought a new radeon that has MPEG2 hardware support. Now if I use Powerdvd to playback these DVD’s with Hardware Acceleration turned on it gets rid of the problem! Plays back the movies perfectly. If I turn Hardware Acceleration off, and leave it up to the software and CPU as I always had the blended fields are back again. So I’m thinking if the MPEG2 hardware decoder on the video card can come up with a way to play it back OK, there’s gotta be an easier way to rip it free of the blended fields. If anyone’s got any ideas it’d be great.

Thanks

[hakko504]

There is AFAIK only one way of getting around this: using Decombs Telecide without decimate (or decimate(cycle=25)) in AVIsynth. If you want a little extra speed you can turn postprocessing off, it should be OK anyway.

[nig103]

@hakko504

Thanks for your reply. I'm still a bit new to this and haven't really played with Avisynth. Avisynth is what creates the .avs file in Gknot isn't it?

Is there a line I can add to my .avs files that will perform a telecide without decimate?

[jggimi]

Uh... If you look at any .avs created by GKnot 0.26, you'll see:#Telecide()
#Decimate(cycle=5) The "#" means they're commented out. Just remove the "#" from the Telecide, and things should work out fine.

For more details click on Start...Programs..Gordian Knot...Docs...and double-click on "Decomb Help.html"

[hakko504]

... and you need to do the same thing to the line that loads Decomb, it should look something like:
#LoadPlugin("C:\Progra~1\Gordia~1\Decomb.dll")

[hakko504]

Originally posted by nig103
@hakko504
Avisynth is what creates the .avs file in Gknot isn't it?
Actually It's the other way around: GKnot creates the .avs that AVIsynth uses. When VirtualDub (or NanDub or...) opens the .avs the AVIsynth kicks in and starts processing the file and feeds the result to VD.

[nig103]

thanks hakko504 and jggimi, I guess the info was there all along ehh.

Thanks again

[nig103]

Just did a test on Casino with Telecide and no decimate and it works beautifully, telecide with decimate(25) gave a little jumpy playback. Thanks again, Hakko and Jggimi.

also thanks Hakko for the little tip on how Avisynth works, it all makes such perfect sense now. Thanks

:)

[hakko504]

You're welcome. It's fun to help others, especially when they post a little follow-up like you did and tell us how it went. That way everybody can share experinces and can come up with new ideas to make things even easier in the future!
:) :cool:

[Vapor]

I only recently did Conan the Barbarian and can confirm that using decomb with telecide() with no decimation worked perfectly.

As Donald said in a more recent post this sort of problem is exactly what telecide is for :)