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Old January 19th, 2008, 12:10 PM   #1
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I'm getting this strange echo effect in AE CS3

This is a little disturbing to me. I just bought a Canon XH-A1 and this was my first little project using it. I am using the Adobe Production premium suite using Premiere to capture. I used After effects to do a special effect and exported back out to 1440x1080 uncompressed since AE doesn't have a preset for that size. Is it me? What preset should I be using between these programs?

Here's a screen cap of the echo effect I'm getting in AE. The original M2T frame looks pristine. I shot it in HD 24p

http://insidestreetball.com/site/web...iththisae.html

Last edited by Sherman Wing; January 20th, 2008 at 08:38 AM.
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Old January 19th, 2008, 01:27 PM   #2
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I'm not the expert you're after but looks like the subject in motion is where it's happening so it could be a field separation problem or a framerate interpolation, or both (or pulldown actually might be the culprit given you're using 24p, but I don't know much about that).
Check that your project framerates etc match the clip interpretation and composition settings in AE. Off hand I don't know if the XH-A1 shoots 24p but still outputs an interlaced signal. If that's the case you might have to re-interlace the clip on the way out of AE in the render settings (I'm not sure if that effect is evidence of that problem, however)
AE should have an output preset for 1080 of every flavour you can think of though.
Hopefully a proper expert will be along to enlighten both of us :)
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Old January 19th, 2008, 06:01 PM   #3
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Thank you for the quick response Murray

Ok Murray, I am completely lost right now. I broke my piggy bank open and scooped up every penny and plunked it down for the Camera and Adobe Production Premium suite because I figured that one suite would inhance my workflow. After reading posts on this forum I decided to try HDV split for capture. I have the old vegas 7 and in preview mode the M2T footage looks fine. I think I figured out the echo thing, I changed the color space to 32 bit and it cleaned it up some. That's 1 hurdle but I'm still looking for a better workflow.
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Old January 20th, 2008, 07:29 AM   #4
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Upon Further review

I captured this footage in HDV split 1440x1080 and imported it into vegas and if you look at this still you can see the cars behind them. I can understand if he was moving fast, he wasn't plus it happens for 4 frames in a row. Has this happened to anyone else is or am I just flat out doing something wrong?
http://insidestreetball.com/site/web...ngwiththis.htm

Last edited by Sherman Wing; January 20th, 2008 at 08:22 AM.
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Old January 20th, 2008, 08:03 AM   #5
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Hi Sherman,

I'm not an expert on AE and in fact rusty even for me since I've hardly touched the program in the last year or so. That said, just from this one frame grab, my initial impression is that this is an opacity/transparency issue, which could easily result from After Effects manipulations. The dark areas (left side of subject's black shirt and hair) seem to have less than 100% opacity, allowing bright areas of background to show through. A masked area with reduced opacity (such as a keying effect), perhaps a time effect like echo, and probably a couple other might give a result like this.

Can you give us some more detail on the workflow?

- Verify that the footage was shot in 24F (which would rule out interlacing issues).
- Verify that the original, unedited capture does (or does not) show this transparency.
- What effects, in what order, did you use on these frames in AE?

Interesting problem.
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Old January 20th, 2008, 08:35 AM   #6
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Ok Pete here is the original frame.
http://insidestreetball.com/site/web...ngwiththis.htm

I do see the start of the problem. I hadn't noticed that before. That is before After effects. That shot is not keyed, that's what makes it a mystery.
Here's the exact workflow:
Shot the clip on my Canon XH-A1 24f. ND filter at 16, Manual mode 1/60 F4.0.
Captured it with HDV split, then imported it into Vegas 7 and Premiere to see which would give me better results. I created 2 different AVI's to work in After effect with. I imported them into AE and did a Demon face effect made famous to me by Andrew Kramer. The output of nboth of the clip was near identical. and both had this problem.
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Old January 20th, 2008, 10:20 AM   #7
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Yeah, that one is a mystery. Given that it is on the original m2t, I can only guess that it is a processing issue related to GOP compression/decompression. The question is whether the in-camera compression is putting it there, or whether it is being generated during the capture utility decompression.

Between those two possibilities, I'd lean towards the latter. Perhaps rather than using HDSplit and then sending the same original to the different programs, try clip capture with different native capture utilities and maybe even a trial of HDLink (included with Cineform products) to see if it is a capture utility anomaly.

If that's not it, I dunno.
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Old January 20th, 2008, 06:36 PM   #8
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Pete, I think you're right, I plugged the Cam directly into my monitor and got to the same frame in there is no effect so I guess I've got to find another capture option. Thanks Pete for sending me in the right direction
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Old January 21st, 2008, 05:43 AM   #9
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The first frame you posted looks like there's a framerate issue - I haven't used an XH-A1, so I can't say for certain, but my guess would be that you ought to be interpreting the .m2t footage as 30 fps, Upper field first, with the appropriate pulldown removal enabled, and your composition should be set to 24 fps. Are these the settings that you're using? As a final thought, I've noticed that if you turn frame blending on in AE CS3, then you get a small amount of blending even when the footage has exactly the same frame rate as the composition. This is barely noticeable with 25P footage on a 25 fps timeline, but might (I'm guessing) be more noticeable with encapsulated 24fps footage.

The second frame that you've posted looks to be a different issue, and it's something that I've noticed on my own HV20 footage. It appears as if the chrominance delta information has either been discarded at compression time or the decompressor isn't interpreting it quite right. The fact that you say that the issue isn't present when you hook the camera up to the monitor is interesting - this suggests that the decompressor is at fault, although I've seen the same artifacts appear using a variety of different programs.
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Old January 21st, 2008, 08:04 AM   #10
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Unlike the 2:3 24p that the HV20 records, the Canon F modes (24F, 25F, 30F) all output a completely progressive frame. There is no interlacing so no need for pull-down during capture, nor AE interpretation. The composition should just be 23.976 fps progressive.

I don't use HDSplit so can only guess; since the artifact showed up in the m2t produced by HDSplit but not when directly viewed from the camera, I'd guess that there is either a setting that needs to be changed in that software or a small bug. That would be sorted out by doing a capture with a different capture utility.
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