Interlace issues but only for a couple of seconds? why?

[defense]

Just curious if anyone knows what may of caused what appeared to be some Interlace issues with a movie I reencoded with CCE..the movie is "BIKER BOYS"..(crappy movie in my opinon) but basically, I noticed that during the movie...towards the beginning...around chapter 4...where the biker boys are in a diner eating..and a waitress walks by...during the walking movements there were some serious arifacts....I've seen this before on an entire movie not encoded properly which had interlace..but this movie is progressive and I kept all settings exactly the same as the original.

The settings were Zig Zag Scan Order, Progressive Frames, Upper Field First, and NON-LINEAR Quantizer scale. What is even more interesting is that you can clearly see this issue for about two seconds when the waitress walks by..I checked the original figuring the issue might be on the original as well..but in this case, it was NOT on the original. The original played this scene flawlessly. Then the issue occurs again, within a few seconds when one of the biker boys walks over to sit down in the diner.

Basically, to my amazement, the entire movie was perfect, other then those two walking scenes in the diner...there was plenty of walking and motion throughout that movie and the issue never repeated itself.

The best way to describe it is there was a full screen of "HORIZONTAL LINES"...which kind of blurred the picture during those scenes...as I said..i'm pretty sure those are what would be considered interlace issues, but if anyone knows more and can tell me what may of caused this...it would definitely be nice to know for the future.

Just when you think you got things down pat, something else surfaces its nasty head.

Any info on what this is and what may of caused it would be appreciated.

[adam]

You said that this movie is progressive, but did you check to see if these specific scenes were interlaced? Occasionally movies will be entirely progressive but just have certain scenes which are interlaced.

Preview this scene in dvd2avi and see if it reports it as film or a % NTSC. If its the latter than you must turn forced film off and IVTC, otherwise you will get interlacing artifacts.

[defense]

What's up Adam? Actually, I thought about that...I didn't rip that particular "scene" persey, I just ripped the "second' vob where the scene occurred and it said progressive....however, I only watched it for about 30 seconds. I'm gonna rip that VOB again and watch it closely in DVD2AVI. If by chance that one scene comes up as Interlace...I have a quick question for you.

I do have one question now though..and that is..why would one particular scene be interlaced..i mean a scene which lasts a couple of seconds..but the remaining close to two hours of the movie is all progressive?

I know usually the introductory credits are usually Interlaced, but I haven't come across a movie where just one scene is Interlaced as of yet..maybe this one is that movie...but any reason as to why this would occur as interlace for just a few seconds out of an entire movie? Thanks

[adam]

Sometimes if they have done alot of editing to the scene, special effects in particular, they will just interlace it, I'm not sure why

[defense]

son of a bitch! You were right Adam! I just ripped the second VOB..and watched it....this scene occurs half way through the second VOB...anyway, the point is that as I was watching it, DVD2AVI kept showing Progressive "solid" and I figured there was no way it was going to change to a solid "interlace." Well, you were right, and I was wrong..it damn sure did change. That ONE SCENE for about three seconds is ALL INTERLACED! That's why I got the damn Interlace issues...man, you're good...

now, my question is, WHY would ONE DAMN scene for THREE seconds be ALL INTERLACED? I mean this movie wasn't one of those "hybrid" films..it was 99% film until that one part! Very intresting...and of course I don't seem to miss anything...I always catch this type of thing..."ABOUT A BOY" had some type of "unfocused" affect for about the same time, but I came to find out the original had the same. Anyway, many people responded to that post and said that's a camera affect, etc...and it would take a lot of money to reshoot, ...but this is very a very similiar issue, at least in terms of that quick "blur" effect or interlace jitter...and for the 3 seconds or less this scene occurs...it just seems odd that this would occur.

Anyway, basically, could you just tell me why this would be Interlaced for three seconds in an entire movie? Also, do you know of ANY other NTSC films which are entirely PROGRESSIVE except for one scene or so? I'd like to see other movies I have which may be simliar to this.

Lastly, are you saying when something like this occurs, I should NOT RUN "FORCE FILM" but I should use IVTC instead, keeping the film @ 29.97 fps and of course NOT running pulldown afterwards as a result of keeping the film @ 29.97 fps? Thanks again in advance...this is really interesting to me because unless you watch the entire movie through DVD2AVI on your hard drive, I can't see how anyone could catch this issue.

[adam]

I can't think of another NTSC movie like this, but alot of times fades to black will be interlaced, because that's just how they were made during editing. I'm not really sure how these types of things come about. Perhaps this part of the scene was added later after everything else had been edited together, and it was more convenient to hard telecine it.

You have three choices. 1) turn forced film off and run an IVTC filter, 2)Turn forced film on and run an adaptive deinterlace filter and hope that only this one scene gets affected , or 3) turn forced film off and encode at 29.97fps interlaced.

Option #2 would probably work fine, but option #1 would be best, though it might take longer to encode. Option #3 would yield the worst results.

Oh, and of course your 4th option is to just encode as normal and live with the artifacts in this one scene.

[defense]

@adam, man, you know, I was thinkin' about that last option real hard, especially since it took 6 hours to reencode that damn movie...but I'm a perfectionist...I can live with the fact that About A Boy had a couple of seconds of blurred video because the ORIGINAL had it and people who really understand why it occurred commented and made me see exactly why it occurred and the costs of reshooting, etc.

This case is a little different and in a way i'm glad this occurred, however, in another way, i'm concerned that I have other movies which may have several scenes that are Interlaced while the majority of the movie is progressive. Well, at least if I come across that again, I'll know how to deal with it.

Basically, my last question is this...I'm definitely ignorant with this type of problem as it has never occurred before. Hopefully it won't occur much more, as it seems impossible to detect without watching the entire movie through DVD2AVI which i'm definitely not willing to do.

Anyway, I think the option i'm gonna choose is your 1st option... to turn force film off and run that IVTC filter. My question though is can I do this using DVD2DVDR? I've never used that IVTC filter, and I haven't used DVD2SVCD in several months...but I know that where that IVTC option is..it says something about "SLOW AS HELL" lol...so if I do it when I go to sleep, I should be ok.

Anyway, just so I understand...let's say I use DVD2SVCD...I would choose to NOT FORCE FILM and IVTC the entire film at 29.97 fps..right? and of course, I would NOT run pulldown in any form afterwards, because the film will already be @29.97 fps..right? Do I have this correct? Thanks once again in advance...i'm gonna research a little more on IVTC, but if you wouldn't mind lettin' me know what you think on this...i'd appreciate it...thanks!

[defense]

I have done much research on this and due to the abundant amount of posts regarding IVTC/Inverse Telecine, I didn't see anything with this specific issue of "one scene" being interlaced..other then this post you wrote to poppyhead mentioning how rare this is and that you haven't seen it..as well as the fact that it would probably occur on the original. I thought the same thing, but the original didn't have this occur..it played the scene perfectly.

adam said:

@Poopyhead. Most of the time the opening studio logos and the end credits are stored as separate cells and are pure NTSC. If you use forced film then you may occasionally see interlacing on these portions. This is a known limitation of forced film, and I think most people would agree its a minimal one. Very, and I mean very rarely, a scene change will be pure NTSC and there is a chance you will see the interlacing. Out of maybe 350 NTSC DVDs this has not happened to me yet, and if it did happen than most likely it would also present itself on the original DVD as well.

Anyway, doing a little more research it appears that IVTC may or may NOT be such a good option. If I were to use DVD2SVCD ..under the DVD2AVI tab there are four settings, one of them being IVTC....could I just reencode this movie, selecting that "IVTC" tab, and then insert the pulldown flags afterwards? Would it keep the quality as close to as good as it is now, while at the same time, "repairing" that scene, so to speak?

let me know when you get a chance,...Thanks