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Camera trails on Active Camera edit

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Jack Sewell
Camera trails on Active Camera edit
on Jun 26, 2010 at 5:23:07 pm

When I cut between cameras in 'active camera' mode, i.e, I have one 35mm cam getting one shot, then it's part along the timeline finishes and a 200mm camera part comes in- instead of a clean cut, I'm getting a sort of morphing effect from one camera to the other (which is actually quite cool in a way-but I don't want it here!)

This is very frustrating, is it just an option somewhere that I don't know about?

Any help would be greatly appreciated......

many thanks,
Jack


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Dave LaRonde
Re: Camera trails on Active Camera edit
on Jun 27, 2010 at 5:37:05 pm

It sounds like you may have conflicting frame rates or 3:2 pulldown issues.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Jack Sewell
Re: Camera trails on Active Camera edit
on Jun 27, 2010 at 7:55:38 pm

what's the 3:2 pulldown issue? Also, how can I have conflicting frame rates if all of this is happening inside one comp?

many thanks.......


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Dave LaRonde
Re: Camera trails on Active Camera edit
on Jun 28, 2010 at 4:41:50 pm

[Jack Sewell] "what's the 3:2 pulldown issue?"

You have to remember that you offered darned few details about the nature of your project to aid in diagnostics -- and absolutely NOTHING about any footage in the project -- so I offer up some speculation.

But to answer your question, it's using 24p footage in a 29.97 comp without removing the pulldown first. Such footage should be used in AE only if you remove pulldown, creating 23.976 fps footage, and work in a 23.976 comp.




[Jack Sewell] "how can I have conflicting frame rates if all of this is happening inside one comp? "

You could have imported an image sequence, which AE defaults to reading as 30 fps, in a 29.97 comp. You could have unwittingly used 25fps PAL frame-rate footage in a 29.97 or 23.976 comp.

But my favorite possibility is this: you're running a version of AE other than the latest one, and you're using video shot on an HDV camera. This is typically a recipe for disaster, and here's why:

Dave's Stock Answer #1:

If the footage you imported into AE is any kind of the following -- footage in an HDV acquisition codec, MPEG1, MPEG2, AVCHD, mp4, mts, m2t, H.261 or H.264 -- you need to convert it to a different codec.

These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.

In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems.

I'm a Mac guy, so I like to convert to Quicktime movies in the Animation or PNG codecs; both are lossless. I'll use Apple's Compressor, Adobe Media Encoder or Quicktime Pro to do it.


Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Jack Sewell
Re: Camera trails on Active Camera edit
on Jun 28, 2010 at 6:12:02 pm

Hi Dave,

Thank you for your detailed response. My apologies for the lack of info.....let me fill you in.

I'm running the latest AE CS5 on a 2.8 i7 iMac. The comp is at 25fps in 1920x1080 res. I'm just using Trapcode Particular / Video Copilot's 'Optical Flares' plug-in and a few PNG files which are being animated. There is no captured live action footage used at all.

There are a few proxy videos in use to ease the processor load. Not sure if this would cause some anomaly. I finished the animation in full and was then onto the process of doing the cinematography on the piece when I ran into the problem.

I've got round it by getting my various shots and bouncing them out separately to then edit together in FCP. I actually wouldn't have used this method and so wouldn't have achieved a few more subtitles to the piece which I really like. So from that perspective, it's a good thing! :)

Am still very curious to know what the problem might be though, as I'm sure it'll make me swear in the future! :)

Many thanks,
Jack



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Dave LaRonde
Re: Camera trails on Active Camera edit
on Jun 28, 2010 at 7:05:22 pm

[Jack Sewell] "There are a few proxy videos in use to ease the processor load. Not sure if this would cause some anomaly."

Well, it's possible, if unlikely. Todd Kopriva at Adobe held a game of "Lets Try To Break AE 10" at this spring's NAB convention. He reports that none of the HDV footage given to him even made AE hiccup. However, the list of footage wasn't encyclopedic, so the jury's still out.

One other possibility: I'm still not sold on Open GL as a useful tool in AE when used to accelerate rendering. If you had it on, try it again with Open GL off when rendering.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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