Field Rendering and scaling frames

[bartrobinson]

You are right, you definitely do NOT want to render at 50% resolution and then scale up using interlaced footage.

I think you are partially right on the way to render at half horizontal resolution, depending on your how your software handles rendering at half horizontal resolution. I think most 3D cameras & software would just render a thinner view of the scene if you told it to render 960 x 1080. Therefore, when you go to stretch the render in post everything would appear 200% wider. I think you'd also have to tell it to render with some sort of anamorphic squeeze applied, so that when things get stretched 200% horizontally in post, they are then the correct width.

You could probably also use something, perhaps like Magic Bullet or re:Vision re:timer and/or Field Kit or whatever to render full res half res progressive, upres to HD, then add interlacing.

[MunicipalOne]

I'm not sure if you have access to a compositing package, but since you are rendering for HD, I'll assume that you do. If I were you, I would render at 960x540 with no interlacing. De-interlace your plate footage, add your half-res render, rescale it to match, and then output everything with one clean set of fields. Mixing and matching fields can be a nightmare...one that is hard to spot until after you've made a delivery.

Since you are in Portugal, I imagine you are working in PAL, which I'm not too sure what your render frame should be offhand (once you remove interlacing). Just make sure you match your frame rates, remove your interlacing, composite, and do a final output with fields.

It would be a shame to go through a huge render just to have to go back and fix it again later.

Hope this helps,

K-W

[Eclectic]

Yap, definitely render progressive picture (no fields) in 50% size and later rescale it and do interlacing. Do not forget to set upper field as dominant.

[bartrobinson]

Yap, definitely render progressive picture (no fields) in 50% size and later rescale it and do interlacing. Do not forget to set upper field as dominant.

How do you suggest he "do" interlacing with progressive frames? The only way that could work out well, IMO, is to render out progressive at 2x fps at 50% horizontal and 25% vertical with half the vertical aspect ratio, upres, then weave the progressive fields into interlaced frames at 1x fps.

[bartrobinson]

Here's another thread you might be interested in. Some interesting techniques mentioned.

http://www.cgtalk.com/showthread.php?t=248836

[Eclectic]

Yes, Bart that will do the job. But, some decent (not extra good) results can be accomplished by simply imorting your progressive video into canopus or tmpeg and exporting it as interlaced video. I didi it few times and result was OK (not perfect). I guess it depends what are You making (I think for demo reel it will be good enough). Anyway, Your advice will give good results.

[bartrobinson]

Yeah, I guess I was just approaching it from the stand point that with HD, it's probably a bigger budget, with less room for imperfections and he's already degrading the quality by rendering at half or quarter resolution (depending how you look at it). So, any more imperfections in the process will compound the quality loss. A client paying for HD, would probably expect a relatively high quality. I'd be surprised if he's making an HD demo reel... :)

[Eclectic]

hehehe....

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