Thanks for your reply but I already knew the problem you mentionned, but it's not the same.
I have to make a move on 6 photographs to pass from one to another and so on. The movement is not clean, there are some "jerks", not a problem with Auto bezier spatial interpolation, it's just not perfectly smooth.
You can see the same problem by just moving a square solid from one point to another : not smooth, especially with slow moves.
Different comps settings and different outputs didn't give a better result.
I can send the AE project if it helps.
Have you got motion blur enabled ? If you move a solid from left to right with linear speed, it will "jerk" (ou saccade comme on dit chez nous ) because of retinal stuff. But if you add motion blur, it will simulate the retinal persistency and it will be smooth.
Looking at your very nice vimeo link, I wasn't able to see motion blur on it (on the first part at least), that's why I ask.
Thanks for your reply Sebastien,
I guess this is the point, I tryed with motion blur on (and played with the advanced part of the comps settings) but it's still not nice.
The move on my photos is very slow and the motion blur didn't help to much, there are still some jerks, did I miss anything?
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Hum... could you upload somewhere your comp so I can have a look at it ? I can't think of anything else right now.
I've played a bit with your project. I could notice little jerks (but not as important as the ones in your vimeo video) with and without motion blur. Turning off the drop shadows seems to give smoother results.
I'm wondering if adding a real camera with 3D layers would give better / smoother result.
I tryed 3D layers with a cam, it didn't give a better result (that's why I try with 2D layers and a null object)
The only improvement I've noticed, is to make a very (very) slow move, but it's not what I want.
I need a perfect move (I have some more to do), so do you think there is a solution or is it a limitation of AE?
Thanks for your help.
Well, to be honest I don't think it's an AE limitation, but I can't figure out what's going on. Maybe it's just a speed problem. I know there are some speeds that can cause problems in animation, depending on the size of the comp, because of subpixel precisions and such, but I'm not that good in this area.
I tryed a simple scale on a photo and noticed also some "jerks", do I have to make a "preparation" for the photos before importing them?
Am I the only one to have this king of problem?
What is subpixel precisions?
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I took a close look at your project and the sample movie and have a few suggestions that should help you solve your motion problems.
First: Your composition is set to the HDV 1080 preset which is non square pixels. You should be using HDTV 25 (1920 X 1080) and Square pixels. Just use the preset in the composition settings. It's best to work in square pixels for several reasons. First, it will give you pixel for pixel accuracy when your image layers are at their default positions providing your images are an even number of pixels. Second, when your image layers are at an angle the sub pixel interpolation will give you a better result especially with thin straight lines. Third, your composition will look better in preview and the app will be more responsive because you won't have to have PAR correction turned on in the Composition window to see an undistorted image.
Second: Many of your images are not an even number of pixels in height and width. *OUE 23-10-41 AVIS LIST M c.jpg for example is 720 X 1321. I would crop it to 720 X 1320. This also improves the accuracy of sub pixel rendering as the image is moving across the composition.
Third: I noticed that many of your layers are scaled above 100% and several have scale values that are not equal. The Avis jaune layer is scaled to
154.9, 169. This distorts the image and also can introduce flicker in the detail and edges on 2D layers. Unless you specifically wish to distort an image the X and Y scale values should always be equal. Scaling up to 160% is going to soften the image but so is scaling down. Your layer scale ranges between about 67% and 170% which is probably acceptable, but if you have layers that are over 150% or under 50% as an average you should probably resize the images in Photoshop and then apply some sharpening to restore some of the detail.
Fourth: Some of you images have high levels of compression artifacts and very high contrast areas. URSS Attaquée.jpg is the image that could cause you the most trouble. I'd take that image into Photoshop and try and reduce the compression artifacts and soften the contrast a bit. Dust and Scratches is a Photoshop Filter that can be used to help improve images with a lot of detail.
Fifth: You should enable motion blur on all layers. This always helps. I'd also open up the Advanced Composition Settings and set the shutter angle to about 360º. You've added a Reduce Interlace Flicker adjustment layer to try and smooth things out but I don't think this is making any usable contribution to the quality of the render.
And last of all, I downloaded the sample video (video-12846205.mp4) and stepped through the clip a frame at a time. I also watched it play using the QuickTime player. It looks smooth to me. I suspect that playback through Vimeo and the GOP compression is causing most of the shudder you're seeing. I'm not sure how you rendered the movie or converted it for Vimeo but here is what I would do.
Set up your Render Queue to output a lossless or nearly lossless movie. I'd use a 10 bit codec like Apple Pro Rez or Black Magic 10bit. Render out a full HD movie. If you need the movie at a different size for delivery then you can either drop your Banc titre 01 Comp (main comp) into a new resized composition, scale it to fit horizontally to keep the X and Y scale values equal, then render a lossless or nearly lossless movie from that composition. To compress the movie for distribution you should use another application. You can use Adobe Media Encoder, Compressor, Squeeze or even Quick Time Pro to compress your project. Make sure your data rate is set to the highest possible for your delivery method and that multi pass rendering is enabled. Vimeo recommends a data rate of 2000 kbits/sec (SD) / 5000 kbits/sec (HD) and a size of 640x480 for standard definition 4:3 video, 853x480 for widescreen DV, and 1280x720 or 1920x1080 for high definition. If you're going to DVD or BluRay then use the authoring app to compress your movie.
These suggestions should solve any movement problems not caused by a stroboscopic effect that is caused with your movement and frame rate cause a steady judder in the movement. To learn more about that search for critical panning speeds.
thanks for the help, I read the suggestions and made some tests :
1- I used a square pixel comp (1920 x 1080).
2- Images have now a even number of pixels in height and width.
3- I didn't distort the image using the scale parameter (and gave integer values like 84%).
4- I tried lots of different photos.
5- I enable motion blur (in the Advanced Composition Settings: I set the shutter angle to 360º , 180° and 720°).
I didn't see any improvement of the smoothness by adding motion blur!
The adjustment layer with the "reduce interlace flicker effect" was not there to smooth things, but just to reduce the flickering.
6 - I used the animation codec and DVCPRO HD 1080i50 codec in the render queue.
7- After reading the explanation of subpixel precisions ( "Layer image quality and subpixel positioning" ) I set the position information for graphics (including the hold position and final position keyframes) to integers and not fractional numbers.
8- I even tried this expression :
In order to help maintain full integer values for position placement (to help reduce apparent blurring) you can use the following expression for the position property:
I noticed a (small) improvement but it's still not enough smooth.
Your expression may hinder the smoothness because it will likely introduce some uneven movement. Here's why. If frame one is at 320.1, 320.1 and frame two is at 320.4, 320.4 then frame three is at 320.9, 320.9 and frame four is at 321.3, 321.3 and frame five is 321.8, 321.8 your movement will be
See how the image doesn't move for 2 frames, then moves a full pixel for the next 3 frames. The pattern of double frame repeating would repeat unless your image moves exactly in whole pixel values.
Here's another thing that can cause apparent juddering playback. Your computer screen display is set to 60HZ and your video is playing back at 25FPS. There's a mismatch in frame rates that's going to give you the same playback problem. Change the display refresh rate to 50HZ and the problem goes away.
Thanks Rick for all your technicals precisions.
I'll try on an external monitor, my computer screen cannot be set to 50 Hz.