Need Quality for keying in After Effects

[aburger]

Hey everyone, I am new here, and need some help. I am working on a project for school with a tight deadline. I shot some bluescreen footage using a Panasonic DVX100. I took that footage to work and had it transfered from mini-DV to DVD using an SDI interface. The quality is great, and I can get a much cleaner key with the higher quality transfer. The problem is: I need to get the mpeg file from the DVD to After Effects Without losing any of the quality. I have FFMPEGX up and running, but what settings should I use to get the best transfer. If I can't use the footage that I burned to DVD, then I have to use a straight firewire transfer, and it doesn't look as good. Any help will be greatly appreciated. Thanks in Advance.

[Case]

I suppose you'll need a codec that supports "Only I-frames", to make it workable for keying in AE. DV seems like the obvious choice. You could use ffmpegX to convert DVD to DV, but as you started with mini-DV, the step to DVD seems unnecessary.

[edDV]

Hey everyone, I am new here, and need some help. I am working on a project for school with a tight deadline. I shot some bluescreen footage using a Panasonic DVX100. I took that footage to work and had it transfered from mini-DV to DVD using an SDI interface. The quality is great, and I can get a much cleaner key with the higher quality transfer. The problem is: I need to get the mpeg file from the DVD to After Effects Without losing any of the quality. I have FFMPEGX up and running, but what settings should I use to get the best transfer. If I can't use the footage that I burned to DVD, then I have to use a straight firewire transfer, and it doesn't look as good. Any help will be greatly appreciated. Thanks in Advance.

I'm not clear what you have on your DVD. What process did you use to get the DVX100 material from tape to SDI? The DVX-100 doesn't have an SDI port? Were you shooting 24p or 480i/29.97?

[edDV]

What I think you must have done is analog capture to SDI. This would effectively blur the edges and result in uncompressed 4:2:2 sampling @720x480i or 720x480p at either 23.976 or 29.97 fps.

Transfering that to DVD should have been done as an uncompressed file rather than MPeg2. You can store about 2-3min of uncompressed 4:2:2 video on a DVD-5 layer.
MPeg2 encoding will introduce degraded edge quality between I frames.


Here is a trick suggested to me by Ultmatte.

DV video tends to be too sharp and 4:1:1 chroma sampling can cause edge steps on saturated edges. First hint is to use green screen which draws more edge detail from the fully sampled Y component. Second hint is to capture from lower bandwidth S-Video to take the sharpness off the edges. This tends to blur out the stepped diagonals.

A better solution is to use an older RGB studio camera or a quality analog Betacam or Hi8 camera* for chroma key foregrounds and then capture as you did from analog component to SDI.


*These older high quality analog cameras are available at cheap prices used as most facilities are or have converted from Betacam SP to DVCPro for field cams and are dumping SD analog studio cameras for HD digital.

[aburger]

The Bluescreen footage was shot in 24p using the DVX100. At work I transfered the footage using a Sony DVCAM deck routed to a Pioneer PRV-LX1 where it was burned as mpeg format (VTS_01_3.VOB). Because After Effects wont accept this type of file off the bat, I am assuming I need to bring the footage first into Final Cut, and export it as a Quicktime format. I am using KeyLight in After Effects to do the keying. The colors are sharper and richer because of the higher end transfer, and I want to keep that quality as I take it into After Effects to do the Bluescreen Keying.

[edDV]

The Bluescreen footage was shot in 24p using the DVX100. At work I transfered the footage using a Sony DVCAM deck routed to a Pioneer PRV-LX1 where it was burned as mpeg format (VTS_01_3.VOB).

OK that is one way to do it but there are a lot of conversions being done.

1. Green Screen would have produced better edges with the DVX-100. Blue is very noisy in these cameras and red/blue are worse colors for 4:1:1 sampling

2. Conversion to 4:2:0 MPeg2 does blur out the chroma but motion compression between I frames isn't the best strategy. Uncompressed or all I Frame recording would have maintained edges through motion better.

3. Import of MPeg2 into After Effects will result in decompression to RGB or YCbCr. In either case the chroma pixels will move in space vs 4:2:0. Artifacts may be introduced.

Because After Effects wont accept this type of file off the bat, I am assuming I need to bring the footage first into Final Cut, and export it as a Quicktime format. I am using KeyLight in After Effects to do the keying. The colors are sharper and richer because of the higher end transfer, and I want to keep that quality as I take it into After Effects to do the Bluescreen Keying.

You will get results but not optimal due to all the processing. If you aren't set up for uncompressed SDI, S-Video analog capture directly to RGB might give better edges at the expense of foreground resolution.

24p has another set of issues.

24p DV or S-video transfer from the DVX100 is done by repeating fields to 29.97fps. By encoding the 29.97 stream to MPeg2 480i you have caused the motion detector to make compression errors that will affect edges. To get a hint at these issues read adam wilt's DVX100 tips.
http://www.adamwilt.com/24p/
If using 24p or 24pa, you should have first captured to Final Cut Pro to restore the 24p frame sequence before further processing. The extra fields in the 480i 29.97fps raw sequence will cause edge errors if processed as 29.97 directly.

[aburger]

Unfortunately, I can't go back and reshoot the footage, and my project is due next week. My only other option is to transfer the footage using a Panasonic consumer Mini-DV camera via firewire into Final Cut, and bring that into After Effects. If I do that, what capture settings do I use to get the best capture for keying the Blue screen?
So, to recap, my only options are to capture using firewire, or use the footage off the DVD, and convert that using ffmpegx. My only concern is the quality of the key. The rest of the footage is secondary.

[aburger]

By the way, if I didn't mention it before, thanks for all the help!

[edDV]

The wilt article discusses capturing 24p or 24pa (advanced) in programs like Final Cut Pro to get a true 24p progressive sequence. That is a good start.

I'm not sure how your project is being graded but I would knock you down for a mixed field 29.97 capture when trying to do 24p and wouldn't downgrade you for natural 4:1:1 artifacts. Once you have 24p in final cut pro, after effects will get good results. That is the basic exercise.

Additional tricks to smooth edges may get you some extra points if you have time.

[edDV]

Here's another good reference document on 24pa but focused on Sony Vegas. Apple probably has a similar guide for Final Cut Pro.

http://sony-937.vo.llnwd.net/dspcdn/whitepapers/24p.pdf