Mixed Interlaced/Progressive DVD

[jpasher]

I've been ripping quite a few DVD movies over the past couple of months, so I have become pretty familiar with using the multitude of programs involved (I still use Gordian Knot for the final stages for its simplicity).

I recently ripped Weekend At Bernie's. When I went into DGIndex to look at the movie files, it shows (roughly) the first 10 minutes of the movie to be interlaced and the remainder to be progressive. I was hoping I'd get lucky and it wouldn't be too noticable, so I created a project using Force Film. After looking at the resulting file in GK, it turns out the interlaced portion at the end is noticably jumpy due to the Force Film.

My question is how should I go about handling this? At first, I was thinking I'd need to encode the movie in two parts: the first x minutes with a Field Deinterlace and the remainder with a Force Film/IVTC. However, this sounds like it would lead to nightmares trying to synch up the audio, since the first have would have to be slowed down from 30 fps -> 24 fps. The latter half would already be at 24 fps.

Any suggestions?

[manono]

Hello and welcome to the forums,

This should probably be in either the GKnot forum, or the AviSynth forum. Anyway, is the footage that was encoded as interlaced truly interlaced (30fps created with video cameras), or just hard telecined film (originally created with 24fps film cameras but encoded as interlaced 30fps)? Do you know how to tell the difference?

Not having worked with that movie, since it is a movie, my educated guess says that you create a 29.97fps D2V file with "Honor Pulldown Flags" checked, and then turn on IVTC in GKnot.

[mic]

FWIW, I's not that uncommon to see NA NTSC DVDs where edited content, or anything specifically for the NA market/region is done 29.976 i, and the rest of the content is orig. film + pulldown (why do extra work :)). While I *Think* it's possible to create mpg2 with both by joining, most of these I've seen actually have separate video -- can confirm by opening indiv. vobs in DVD or other player. If it is separate, audio in my experience is probably separate, and you can do as planned. If not separate, render 1st portion to avi, de-muxing/converting audio, IVT those as pair (V/Dub?), then process from that point on or as force film. I haven't had audio prob. if IVT run with audio as pair.

[jpasher]

Thanks for the forum tip. Since I'm using a few different utilities, I didn't know where it best fit.

I have created a DGIndex project using the Honor Pulldown Flags setting and looked at the interlaced portion in GKnot. After sampling about 15 seconds of the video, it appears to follow the 3 progressive, 2 interlaced frame format. At this point, do I just try an IVTC in GKnot? What would cause DGIndex to think the first 10 minutes of the movie were pure NTSC Interlaced but it flipped to pure Progressive afterwards? Incorrect flags in the frames?

Trying to understand the actual work behind the Force Film does in DGIndex, does it simply perform the "IVTC" by looking strictly at the flags in the frames? Does the IVTC option in GKnot do a lot more "analyzing" of the frames to make this mixed interlaces/progressive movie work properly?

[manono]

Hi-

Good for you. You've actually had a look at the source. If what you found holds true for the other parts encoded as Interlaced (you should check it in several different places), then the NTSC portions are "hard telecined" or telecined prior to encoding, and for one reason or another the encoder didn't IVTC it, keeping 29.97fps stored on the DVD, unlike the Progressive FILM parts where 23.976fps Progressive frames are stored. IVTC should work fine to restore the whole thing to Progressive 23.976fps.

It'll say Progressive FILM only when Progressive frames are stored at 23.976fps. It'll say Interlaced NTSC when it's hard telecined, when it's true 30fps NTSC Interlaced, and usually when 30fps Progressive frames are stored on the DVD. Theoretically, if parts are 30fps Progressive, it could say Progressive NTSC, but I've seen few, if any, examples of that.

DGIndex isn't mistaken. When 29.97fps is stored on the DVD, by definition it's NTSC. It's not incorrectly flagged. Edited badly, maybe, incorrectly encoded, maybe, or older and less precise hardware encoders used, maybe, but not incorrectly flagged.

If you try and Force FILM on hard telecined 29.97fps content, you'll most likely get interlacing and jerky playback. Force FILM only reads the flags. If it's not flagged as Progressive FILM and you Force FILM, it'll just drop 1 frame in 5 without any kind of frame reconstruction (I think-could be wrong there), and you'll wind up with a mess. A true IVTC does do a lot more analyzing in order to reconstruct the frames from the fields, and then to drop the one duplicate frame in every five.

What you have is well within the DVD specs, and the DVD will play fine on a standard Interlaced TV set. But those NTSC parts can look horrible when played through a software DVD player on a computer monitor, and also on an HDTV if the Progressive Scan DVD player is also only a flag reader. They'll just deinterlace the non-FILM parts.

[jpasher]

For the others that might try encoding this video, I ran the movie through DGIndex without Force Film, then IVTC'd from GKnot and the encoded video looks good to me. I cannot see any interlacing effects left behind.

Thanks for the tips.