Deinterlacing deinterlaced video?
 

Hi all,

This may well be the wrong forum for this question, and if so I apologize!

I have a video project (SD) that contains both interlaced and deinterlaced footage. Ultimately I'll deinterlace the whole thing and "filmify" it with the help of Magic Bullet. However, what of the already-deinterlaced shots? Will deinterlacing again harm it?

Ed,

If the "already deinterlaced" clips were 60i and are now 30p thanks to being deinterlaced, then those will not fare well when trying to convert to 24p with Magic Bullet (or any other 60i->24p conversion program). 30p doesn't go into 24p nicely, it'll just be a bunch of frame blending. All of the manuals and guides will tell you so. You need pure 60i footage to do a good 24p conversion.

Josh

Tell us more about your settings and we can be more helpful.

What framerate do you hope to finalize the project in?

Ah, sorry, I knew I was gonna leave stuff out.

What I think I'd actually be doing is going from 60i -> 30p -> 30p again.

Here's the dealie: I've got someone adding some CG elements to a number of shots, and I'm reincorporating the new shots. When the CG stuff is added to it, the resulting file is deinterlaced. So I'm incorporating some deinterlaced footage into an otherwise-interlaced scene. But ultimately I want to use Magic Bullet to add some effects and output the final product to 30p.

I should add that while the fellow doing the CG work could re-interlace the video, it'd double the rendering time and is not really a viable solution.

If it's 30p the motion should be fine, but deinterlacing already deinterlaced footage is going to produce a drop in resolution. Once you deinterlace from 60i to 30p you lose resolution. Assuming that you are on a 29.97fps timeline in your NLE deinterlacing that from a timeline that has both 60i and 30p the reolution of the 30p footage will decrease in resolution even more.

What NLE are you working on?

Are you planing to export that timeline to a self contained movie and then deinterlace that?

Most NLE's have a deinterlacer plug in. I would deinterlace the 60i footage as you edited.

Thanks Tony! Responding to your questions:

Adobe Premiere 6.5

That was the original plan. However, I can use Premiere to deinterlace the other footage, and then export the whole thing and use Magic Bullet from there.

However, this raises an additional question: if I simply uncheck "deinterlace" in Magic Bullet (in After Effects) will I be all set then?

I notice that virtually any time I export video from AE the footage is a little juttery (looks like it has a lower frame rate), whether I'm using Magic Bullet or not. Is there a reason for that? It seems to be more than simply deinterlacing the video. I actually like the effect, as it feels more filmlike, but I'm wondering if it's actually lowering the resolution as well.

EDIT: That is to say, AE seems to automatically deinterlace my footage, so if I want to use Magic Bullet's look suite, my footage is going to get double-deinterlaced no matter what... Is that avoidable?

Hmmm... not sure I'm capable of answering some of these questions. I haven't used Premiere in years.

Are you using Magic Bullet and AE just to deinterlace?

Nope, I'm also using it for the Look Suite.

HOWEVER... I think I solved my problem. Turns out if I right-click on my video file(s) in the bin and go to Interpret Footage > Main... then I can turn off deinterlacing!

So... if I deinterlace my non-CGed footage in Premiere and export the whole timeline, I can apply the looks I need in AE with Magic Bullet without deinterlacing anything a second time!

Cool, sounds like problem solved. You might find magic bullet editors helpful also. You can apply the same looks in Premiere.

Ed,

Hey, that's one solution. Unfortunately, Premiere is one of the worst deinterlacers out there. You'd have noticibly better results sticking with 60i in Premiere and using MB to deinterlace. I've seen nasty artifacts from MB 60i->24p deinterlace, but 60i->30p is pretty solid. MB is also pretty smart, so if you there are some CG shots in there, it should just pass them through without messing them up.

Avoid Premiere deinterlacing like the plague!!!

Josh

Ah, that's very good to know. In that case, I'll try the other way around and deinterlace MB-style!

Thanks Josh!