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Render different than preview… baffled!
One frame in the render of my composition is off. Everything else is perfect, but at 5:05, for a single frame, one of my three layers is shifted left by a few pixels. This does not appear in the timeline preview. I’ve tried rendering 8 times now, and it always comes out the same.
If I render just a short section (1 second) that contains the bad frame, the render comes out fine. It’s only if I render the full (15 second) comp that the frame is shifted.
Interestingly, the frame that is shifted is right after a position change on that layer. I have two position keyframes on that layer — one at the affected frame, and one at the frame prior, which is just fine. I do not have graph editor turned on for that layer.
I tried creating additional keyframes before and after those two frames to force the position to conform on other frames. I have tried making them all “hold’ keyframes.
This is driving me batty trying to figure it out. Anyone have any ideas what might be causing it?
Before you start sending me a barrage of simple answers, let me offer the following:
-Open GL is off for rendering, and off for previews.
-Multiprocessing> Render multiple frames simultaneously is turned OFFI am using no effects. Masking and motion tracking (position and anchor points) only.
Codec is DVCPRO-HD 720p at 23.98.The clip in particular was originally shot on HVX at 720p60 (not overcranked). I used frame rate converter in FCP to conform the clip to 23.98 and created a ‘reference clip’, which is what AE is accessing. Next thing for me to try is to create a self-contained 23.98 clip… any other ideas?
FCS 3
AE CS4
ProTools 8.0
OSX 10.5.8
MacPro 2×2.8GHz Quad
4gb 800mhz DDR2 -
7 Replies
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The frame rate is really 23.976, not 23.98; if you are interpreting footage at 23.98 and outputting 23.976, I’d expect weird things to happen every now and then.
If you are in fact using 23.976 already, you might also try purging your caches.
Does the frame in question look correct if you use Composition > Save frame as… > File? If so, you might try rendering to an image sequence and simply replacing that frame if necessary.
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events -
… or don’t use AE to render to DVCPROHD. I’ve found that the process is buggy.
I use AE to render to the Animation codec, then use QT Player to export it to DVCPROHD.
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The self-contained version didn’t work — same problem. Odd…
Rebooting didn’t work, either. Guess I’ll have to try trashing prefs, then. Weird that it’s so persistent.
FCS 3
AE CS4
ProTools 8.0
OSX 10.5.8
MacPro 2×2.8GHz Quad
4gb 800mhz DDR2 -
Well, I guess if AE isn’t reporting 23.98 properly, what’s to say FCP, or even my HVX200 is reporting it properly. I’m just assuming the footage all works in the same time base, regardless of whether it’s
Plus, what I’m rendering is 15-seconds long, and the error occurs at 5 seconds in. I’m not sure that’s long enough to feel a discrepancy between 23.98 and 23.976. Well, but I suppose it could be 2000-or-so frames into the original clip…
I suppose a simple test would be to chop the original clip down a few frames and see if the error happens in the same place, or that many frames later?
At this point, I’ve solved the issue by chopping the beginning of the comp down 20 frames or so. It renders just fine — completely seamless! So I guess that makes it even more of a mystery.
FCS 3
AE CS4
ProTools 8.0
OSX 10.5.8
MacPro 2×2.8GHz Quad
4gb 800mhz DDR2 -
Yeah, that’s too bad. Seems tedious to do things that way. More HDD space, more time, more steps, more to keep track of…
FCS 3
AE CS4
ProTools 8.0.3
OSX 10.6.3
MacPro 2×2.8GHz Quad
4gb 800mhz DDR2 -
Ah, thanks for the correction! It’s refreshing to know AE calls a spade a spade. My comp says 23.98 in AE, so now I’m *convinced* that’s the problem. Will try and report back.
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OK, well that settles it. Changing the composition frame rate to 23.976 fixed it. I’m upset that FCP inaccurately reports my clips’ frame rates to be 23.98, when the HVX actually shoots them at 23.976. Are they running short on decimal places or what?
FCS 3
AE CS4
ProTools 8.0.3
OSX 10.6.3
MacPro 2×2.8GHz Quad
4gb 800mhz DDR2
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