HELP: 16:9 Widescreen to 4:3 Letterbox Conversion (Severe Combing)

[Bill Binder]

I can't find an answer to this anywhere, so I hope someone here can help...

My setup: Video shot in true 16:9 widescreen NTSC DV format (720x480 at 1.22 pixel width). Let's be clear here, this is real TRUE widescreen NTSC DV, not letterboxed/cropped 4:3, that I'm starting with.

My problem: trying to render the original 16:9 frames into a letterboxed 4:3 frame video. I've been successful at getting a 4:3 video with my 16:9 image letterboxed in it, but I'm getting TERRIBLE combing/tearing/interlace motion artifacts. The problem is really bad and very noticeable with any horizontal movement in the frame at all.

I've tried doing this so many ways, I can't remember them all, but here are a few. First all clips were widescreen, my project was widescreen, then I rendered to 4:3. Next, I tried my clips widescreen, project 4:3, render to 4:3. Both techniques got me 4:3 video with my 16:9 image letterboxed inside of it, but the combing/sheering was god awful anytime there was horizontal movement in the frame. I also tried things like force resample and reduce interlace flicker, but still had problems. I think this has something to do with the combination of scaling my 16:9 image down in size to fit inside a 4:3 frame in combination with the interlacing. It's as if the resizing is totally screwing up interlacing. Thing is, I want to keep it interlaced because eventually I want to render to 4:3 DVD MPEG2 format.

Another thought I had was to render out to 30p widescreen DV essentially deinterlacing the full widescreen footage into a full render first. Then bringing that render back into vegas and then making project 4:3, thereby introducing the letterboxing AFTER I have deinterlaced the whole thing. After that, re-render out to interlaced NTSC again. Another thought along those same lines is to start with the widescreen interlaced events, make the project widescreen DE-interlaced, then render out to interlaced 4:3 (to get the letterbox). But both of those options seem overkill because I deinterlaced only to reinterlace which sounds like a bad idea in general.

Any help here would be greatly appreciated!!!!

Thanks...

[Matt Ockenfels]

Hi Bill,

A couple of questions to get things started...

How are you shooting your widescreen? Which camera? Are you using an anamorphic lens? Progressive or interlaced?


Cheers,

-Matt

[Bill Binder]

Many people don't believe me, but I'm shooting 29.97 interlaced NTSC widescreen video with a 1.22 pixel width on my Panasonic GS400 3-CCD camcorder. This is one mean "consumer" camcorder if you've never heard of it. This "consumer" camcorder is not only 3-chip, but when shooting widescreen it uses the whole image on the ccd's -- it's not smooshed, zoomed, or cropped.

So the deal looks like this. If I shoot widescreen. Import events as widescreen. Have the project settings widescreen. Render out as MPEG2 widescreen, and burn to DVD as widescreen... You get the idea, widescreen end-to-end, the DVD looks perfect at 16:9 on a widescreen TV, and if the DVD player is set to 4:3, it'll look perfect letterboxed (letterboxing by DVD player).

HOWEVER, I want to render out as 4:3 NTSC DV, letterboxing my full 16:9 image. This is NOT about masking a 4:3 to "look" like 16:9, this is taking true 16:9 and making it letterboxed in a 4:3 video. AND, I can do this in Vegas, it works! BUT, I get TERRIBLE INTERLACING problems no matter what I do.

Did that help clarify my question?

Thanks for asking...

[Brian Kennedy]

Bill - this probably doesn't help much, since you already have interlaced video you want to make 4:3, but if you shoot with the GS400 in 16:9 mode at 30p, it can be resampled to 4:3 letterbox in Vegas and looks good. The GS400's "frame mode" 30p looks very nice and doesn't lose any resolution compared to interlaced, even though it isn't "real" progressive video. I haven't tried taking 16:9 interlaced video down to 4:3 in Vegas, but also keep in mind that if you render to 16:9 and put it on a DVD, your DVD player will automatically letterbox it on a 4:3 television set, yet play full 16:9 on a widescreen television.

Sorry if I am stating the obvious. Another obvious thing -- also keep in mind you don't see the interlace artifacts so much on a TV as you do on a computer monitor. Are you saying the resulting video looks bad on a television, too?

[edit:] I guess I should have read your above reply more carefully. I see you already knew most of that. If I were you, I might next try blending the fields in Vegas using the techniques outlined here and on the VAAST site, to turn the interlaced into a progressive-like video, getting rid of the jaggies. Sorry to hear you're having problems, and I hope you find a good solution!

[Kyle Ringin]

I think the best thing to do is to deinterlace then resize. You'll potentially lose a bit of resolution, but you will be going to 4:3 LB anyway, so maybe it won't matter.

Out of interest, why would you want to do such a thing? VHS?

Cheers.

[Matt Ockenfels]

Bill,

Give this a try....

Create a new project. Put one some footage in it. After adding the footage go back to Project Properties and make sure the pixel aspect ratio is 0.9091(NTSC DV) Change it if its not.

The footage should now appear one of two ways: (a) squished or (b) letterboxed.

If letterboxed, render and see what happens.

If squished, right-click on a clip and go to properties->media. Look at aspect ratio. If it says 0.9091 (NTSC DV) change it to 1.2121 (NTSC DV Widescreen) and try a render. If it initially says 1.2121 (NTSC DV Widescreen) ..... that would be wierd.

If this does not work send me an email and I'll try to get some footage from you to look at .... I am curious now.

Cheers,

-Matt

[Bill Binder]

I played around with this more last night, here's a few more comments...

(1) If you read my earlier posts, you can answer some of your own questions. For example, yes my events are PAR=1.22, and yes my project PAR=.90, and yes when I render to PAR=.90 NTSC DV the video becomes letterboxed just like I want it to. None of that is the problem, I understand all of that, except it is also possible to leave the project PAR=1.22, then just render out to PAR=.90, that works too. THE PROBLEM IS COMBING!!!

(2) I tried two different things that seemed to help a lot. I thought I tried one already, but maybe not. For starters, clicking "Reduce Interlace Flicker" on only the events that were having big problems helped a lot. In fact, that may be enough to make it work well enough. I also tried making my project setting PROGRESSIVE scan using blend to de-interlace, then rendering out to interlaced NTSC 4:3 DV, which is my goal. This also seemed to help the problem a lot. However, I'm not sure if a de-lace/re-lace cycle should be needed, and it seems like a very destructive process.

(3) In the next couple of nights, I'm going to try to print-to-tape all four scenarios and watch them on my TV. The first will be the control, which will be widescreen end-to-end (I have a widescreen TV). The second will be simply dropping the project/render down to 4:3 letterboxed. The third will be using reduce interlace flicker only. And the fourth will be the full deinterlace in the project, with a interlaced 4:3 render. After printing all four (I'll just print a scene where this is happening the worst) to tape, we'll see what each looks like on a real TV -- then I'll report back.

(4) This seems to almost certainly have something to do with the fact that the frame is literally being resized smaller in combination with the interlacing. It's almost as if after resizing each interlaced field, the lower/upper paired fields don't line up against each other for the combined frame as well as they did before the resizing.

(5) Yeah, VHS, one more good reason you might have to do this. <SMILE> Trust me, the more people who shoot in real widescreen are out there, the more people who will need to do this every once in a while. Problem is, whenever I say "letterbox" on the Net, most people immediately think masking 4:3 to look like widescreen, which gets me nowhere because I'm doing something very different.

Thanks for all of your help, I think I'm getting close to a solution, albeit a less than desireable one...

[Michael Wisniewski]

I had a deadline when I encountered the same problem. I ended up copying the anamorphic DVD to make the VHS tape. That was the cleanest solution I could come up with that got rid of the shearing/combing.

[Patrick Jenkins]

Take your original project and make sure you've got both deinterlacing (either blended or interpolated) and resampling (smart resample or forced resample) on combined with lower field first. You mentioned that you have tried this already, but I just tried it here and it worked as expected - so maybe triple check your settings. The combing occurs because you're moving fields around from one vertical dimension to another - and the fields no longer realign after the fact (you're shrinking 480 alternating fields down to roughly 360 alternating fields so there's no way to get a 1:1 resize) . There's no way around this short of deinterlacing.

If you really want that video feel (interlaced rather than quasi-progressive), convert the whole 60i to 60p, then resize down (while leaving interlacing for the project on). You'll be able to keep the full 60fps smooth video feel while losing the combing --- but at the expense of overall decreased resolution and sharpness.

You can also try turning off all builtin interlacing and applying Mike Crash's smart deinterlacer to the whole thing.

[Bill Binder]

Thanks for the help. Let me get something clear... The "Blend" deinterlace should be set in the project settings, but the "smart resample" or "force resample" is set on each event switch. Is that correct? Or can I set resample for the project as a whole? Also, I was always confused by this: how can I deinterlace in the project settings but NOT make the field "progressive". What exactly does it do when you deinterlace, but leave "lower field first" showing instead of "progressive". Thanks for all of your help!

[Laurence Kingston]

Strangely, when you convert aspect ratios from 4:3 to 16:9 and vice versa, it will do this and the converted footage will still be interlaced correctly, but Vegas uses the deinterlace settings to do this even though the interlace is maintained.

I would not use the Mike Crash deinterlacer for this because you'll end up with deinterlaced footage at the new aspect ratio that has the jerky look of deinterlaced footage.

There is several free scripts on the VAAST site and elsewhere that will rescale all the clips in a project to whatever you select in the project properties window. You will need to make sure that you have the deinterlace settings in the project settings window turned on. If you turn them off you will get horrible interlace combing. None the less, your converted footage will still be interlaced and the motion will look as smooth as it did before the conversion.

I have experimented with both the "blend fields" and "interpolate" deinterlace settings and can see no difference no matter how closely I examine the frames with either setting. For an actual deinterlace there is a huge difference, but for an aspect ratio change both methods look identical.

[Guy Bruner]

Interesting discussion, guys. That GS400 is an amazing little cam, huh? Bill if you need some web space to post some video samples or frame grabs for us to see, you are welcome to put them in the Members Album at www.fortvir.net. If you put video there, please keep the size 10 MB or less...that pretty much precludes raw DV. BTW, I like Michael's solution for VHS...just copy the DVD to VHS tape.

[Bill Binder]

Guy,

FYI: I'm "Tainted" in your Panny 3CCD Forums... <SMILE>

-- Taint


P.S. Thanks for all of the tips! I've had lots of success using "Reduce Interlace Flicker" on the events that had really bad combing after the conversion from true 16:9 to 4:3 Letterboxed (the 16:9 image letterboxed inside of a 4:3 frame). Also, like the guy above said, changing delace to "Blend Fields" but leaving Interlacing at "Lower Field First" also seemed to help a lot. I seriously wonder what Vegas is doing under the hood with this. I vaguely remember something in the manual about how it handles re-sizing of interlaced footage -- something about delacing, resizing, then relacing comes to mind, but that seems kind of desctructive to me. Interesting problem though...