View Full Version : green\bluescreen pipeline help

01 January 2005, 01:41 PM
hi all,

- i've also posted this in the aftereffects forum. so sorry for double posting -

i've been given the chance to "tinker" with a digibeta camera and greenscreen studio, so i thought i'd try and learn some new techniques. however i have a couple of questions about workflow and a few technical issues.

i'm planning on shooting PAL digibeta, dumping into an avid and then exporting into some standard (uncompressed) pc format so i can muck around with the footage with aftereffects.

1 - what do i do about the fields? i initially thought about just removing them and working entirely with frames. this would make things a lot easier in after effects. the problem lies, if i go back into the avid with these "frames" will it look rubbish?

2 - if i keep fields, does anyone have any pointers on how to deal with them in after effects? or even better workflow examples or links to tutorials?

sorry if this is an open ended question, but i've spent ages trying to find any information on the topic.

many thanks in advance


01 January 2005, 03:17 PM
AfterEffects should be able to deinterlace the footage for you...

So instead of working with 25 720x576 frames per second, you're actually working with 50 720x288 frames, where each pixel is double height.

If the final output needs to be interlaced, then you'll be better off doing it this way. However, if you can, I'd suggest getting the camera to shoot in progressive mode, so you're actually working with 25 full frames per second. If you're just messing around, then I'd definately recommend going this route.

01 January 2005, 08:51 AM
thanks hugh

"So instead of working with 25 720x576 frames per second, you're actually working with 50 720x288 frames, where each pixel is double height."

now i (nearly) understand ;) sorry to sound incredibly dumb, but do you have any more info on this technique. or know of any tutorials\documents that could help me?

it looks like i'll be able to output my tests back to digibeta useing a "borrowed" avid suite. so as far as i know i just need to know the correct field settings the avid uses, use the same in after effects and my 3d software(for the backgrounds), use the technique above and then at the end of it all after the keying. dump it back into the avid. phew......easy as that:)

this sounds like a plan of action to me, anybody see any flaws in my master plan?

many thanks for any help


01 January 2005, 09:18 AM
Most compositing packages (well, I know Shake and Digital Fusion do, and I'd suspect Combustion and After Effects do aswell) will have the option for the FileIn/Loader/whatever to say that the footage needs deinterlacing....

In Shake, this then means that you can go in 0.5 frame steps, and see each field.....

It's been a long time since I used After Effects, though....

The Avid probably isn't the best place to make changes to this kind of thing - if it was shot interlaced on the camera, you should really be working interlaced.....

01 January 2005, 11:13 PM
I found this in a 30 second search on Google. Of course, I knew they were there somewhere.

Adobe Fields and Frames TechDoc

AVID Knowledge Center

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01 January 2006, 12:00 AM
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