Which effects workflow for chromakey?

A

andy_starbuck

Well-known member
Q1: I'm trying to decide which effects workflow to use, Mac/FCP->AE or PC/Raylight/Premiere->AE?
Q2: Does one path provide a *real* resolution advantage?
Q3: How do I get output from PC/Raylight back to Mac/FCP for integration?

Looks like I have a lot of expirementation ahead. Any advice or insight would be appreciated.

Here's the background and requirements:

I have green chromakey footage shot in 1080i24pA and two possible paths for effects work. Eventually the footage must recombine with the rest of the project shot in 720p24pN on a MAC/FCP. Destination is SD/DVD for now, with a requirement to preserve HD quality for the future.

Raylight looks easier to work with on the front end, because it performs reverse-telecine on the 1080i24pA automatically. On the Mac, I have to ingest the footage using FCP, then perform reverse-telecine with Cinema Tools. Also, Raylight appears to give a resolution advantage (1920x1080 vs. 1280x1080).

Integration of the results looks easier on the MAC, because the DVCPROHD codec is available. On the PC, I think I'm stuck rendering out uncompressed to transport the footage back to the MAC to preserve 4:2:2 color for CC.

Here are my questions in more detail:

Q2: Is there a real resolution advantage ??
Raylight provides 1920x1080 at 24p. FCP 5.0.1 seems to provide only 1280x1080 at 24p. Is this a real resolution advantage?
Q2-A: What is the real resolution that the HVX is recording in 1080i24pA ?
Q2-B: Is Raylight interpolating up to 1920? Is FCP reducing down to 1280? Is either providing the true recorded resolution?
Q2-C: Does the extra resolution make a differnence in chromakey if the output is 720p?

Q3: From PC to MAC/FCP ??
After the effects work is done, I need to get the footage back to the MAC/FCP for integration with the 720p24pN footage. I want to preserve the 4:2:2 color because I need to color correct between the 720p and the effects clips. The Raylight codec is fantastic -- but apparently not available on the MAC. That leaves me with a problem transporting the output back to the MAC/FCP.
Q3-A: Is there any appropriate shared codec, or do I have to output uncompressed Quicktime or uncompressed AVI ?
Q3-B: Where should I reduce the resolution from 1080 to 720? Premiere? FCP? Quality difference? File size difference?
Q3-C: If I must use uncompressed, which is like 10GB a minute, how do I ingest the files on the FCP side to get them in DVCPROHD/Quicktime so that its a manageable file size?
 
Hi Andy...

Q2: No, this isn't a real resolution advantage... the source footage is only 1280x1080. Raylight makes it "appear" to be 1920 by 1080 (it's a pixel aspect thing) for easier integration with software that wants to see standard full raster 1080.

Q2-A: see above, 1280 by 1080. And it's not "filling" that size with real resolution either... it's better than recorded 720p, but not by much vertical and only 15 to 30% horizontally.
Q2-C: In HD, your best source from the HVX is what you have shot.

I'm staying away from the PC-MAC workflow side of your questions, as there are many options and I'm no FCP expert...

It might be easier to just do the whole job on the PC if you're going to use it for FX work... using Cineform and Premiere/Vegas would give you a solid, EASY workflow for both editing your 720 footage mixed with your 1080FX stuff.

Or, stay entirely on the MAC where QT DVCPRO 100 files are native...

What do you need to do on the PC?

Regards,

Jim Arthurs
 
Jim,

Thanks so much for your reply!

My reason for looking at the PC workflow was because of the apparent 1920x1080 resolution. Also, I sometimes collaborate on projects with people using PCs and Premiere, and wanted to know if there was a benefit to working on the MAC or on the PC.

I ran tests most of the day and discovered that getting to After Effects / Keylight made the biggest difference in compositing quality, no matter which platform. Premiere's chromakey required a lot of tinkering and never looked as good. FCP's chromakey produced results almost as good as AE/Keylight, but required more adjustments.

I tested compositing a clip on the PC in 1920x1080 (Raylight+After Effects/Keylight) and compared it to a test composited on the MAC 1280x1080 (DVCPRO100+After Effects/Keylight) and they produced similar results. So I see the wisdom of staying in QT DVCPRO100 and working on the MAC for the current project.

The only thing I need now is to understand better how to use Cinema Tools to remove the 1080i pulldown to get back to 24p.

I also ran a number of tests trying to transport output from AE/Mac to Premiere/PC and from AE/PC to FCP/Mac, and came to the conclusion that its painful to cross codecs, because the common denominator is uncompressed QT and AVI files that are *huge*. In the future, if I'm collaborating on a PC/Premiere project I'll plan to do the chromakey on the PC and stick with the Raylight codec. And If I'm working on a MAC/FCP project, then I'll stick with the DVCPRO100 codec.

Any advice on reverse-telecine of 1080i using Cinema Tools?

Thanks!
 
Cinema Tools has a bug that causes it to mis-mark the reverse telecine file it generates. The new 23.98 file shows up in Finder as 640x360. After Effects interprets that as the correct size and reduces the resolution, making the clip useless. FCP will recognize the clip's true resolution.

So... Instead, use the "Interpret Footage" feature in After Effects to remove the pulldown.

Chromakey on the MAC using FCP:
1) Import the 1080i24pA clip from P2 to FCP/Quicktime using Final Cut.
2) Use Cinema Tools to remove the pulldown to 23.98.
3) Import and use the clip in FCP.

Chromakey on the MAC using AFTER EFFECTS:
1) Import the 1080i24pA clip from P2 to FCP/Quicktime using Final Cut.
2) DO NOT USE Cinema Tools to reverse-telecine. Cinema Tools has a bug and marks the reverse footage as 640x360 in Finder. After Effects will see the footage as 640x360, interpret it that way, making the clip useles.
3) Instead, use After Effects "Interpret Footage" to remove the pull-down from the original FCP/Quicktime clip.
 
Jim, thanks so much for the information. Your keys look awesome. I've been stunned at the results I've gotten with 1080 in After Effects and keylight. Its really amazing when it works.

Is there a reason to move from 5.0.4 to 5.1.1 ? I've read that the pullodwn on import in FCP doesn't work. Have they fixed the problem that Cinema Tools produces reverse telecine files marked 640x360 for Finder, Motion, and After Effects. I also read that the 1080p24 preset is not provided. Those were my three reasons to upgrade. Any others?

Thanks!
 
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