Track motion or panning speed problem

Skeetorama wrote on 2/6/2008, 9:57 PM

I am trying to have a video sequence pass across my visual window at a constant speed. If I use either the pan or track motion function, it is obvious that the motion is NOT constant; rather it accelerates to a given speed, and then slows the speed of motion down to settle at the end. That is fine for short pans, but I am trying to get a constant speed of motion for the effect I am looking for (the motion begins off screen and ends off screen.) Does anyone know a straight forward way to get a constant speed for either method? The results I am getting are more than annoying; they look lousy. (the smoothness setting doesn't make any signififcant difference in the speed either.)

Comments

Kennymusicman wrote on 2/7/2008, 7:06 AM

right click the earlier keyframe, and select "linear". Sounds like you have a curve setting, such as smooth for your movement

Skeetorama wrote on 2/7/2008, 8:12 AM

Thanks for the great insight Kennymusicman - I did not know about those adjustments. HOWEVER, all of those settings (with the exception of the "hold" obviously) appear to accelerate to a given rate at start and slow gradually down at the end of a long pan. My hope would be a calculated pan speed that will start at the first keyframe, and end on the next exactly - with no aceleration or deceleration. I would have supposed linear would have done it for me, but it does not. Any other ideas?

Chienworks wrote on 2/7/2008, 8:18 AM

Do you have both the beginning and ending keyframes set to linear? Do you have smoothness set to 0.0% for both of them?

Kennymusicman wrote on 2/7/2008, 8:39 AM

Also - are there just 2 keyframes, or more - just checking :)

Skeetorama wrote on 2/8/2008, 8:09 AM

As for the number of keyframes, there often are just two - one at the beginningmarking the start of the motion and one at the end marking the end point. I have experimented with multiple keyframes, and it seems to make little real difference. It is possible that a LOT of keyframes might cause it to be better - I haven't explored that possibility.

As for the linear and smoothness issue: I found that the default on my setup was linear already - so no change there helped. I have experimented with the smoothness as well. It does appear to have some bearing on it, specially in shorter pans, but in longer movements the acceleration and deceleration is still very obvious.

I appreciate the interaction on this. Thanks!

autopilot wrote on 2/8/2008, 9:12 AM

Well, if you're just going from A to B, all you need is two keyframes. Maybe your computer is bogging down at the sight of these keyframes & maybe other things going on at the same time. Highlight the area with your loop region and do a Shift B, and see how it looks rendered.

Skeetorama wrote on 2/8/2008, 10:47 AM

The problem shows up in the rendered version, not just in the timeline playback. I understand that this problem would not be seen in every situation. There are clearly times when the acceleration and deceleration would be of no consequence. However, this is not one of those times!

Kennymusicman wrote on 2/8/2008, 11:17 AM

Can you send the veg file to us? Don't need the media, but just the veg file - as obviously we aren't getting this problem with our projects, so maybe we can see why you're getting it on yours

Skeetorama wrote on 2/8/2008, 11:28 AM

Hello Everyone -

I have finally gotten around it. Although I think the issue still exists, I was able to start the motion out of the visual area, and then end it off visual area in such a way that it could work. I also used the track motion, rather than the panning. This allowed me to do more with the smoothness, and my output looks fine now.

As is often the case, the problem was not necessarily the software, but a nut lose on the keyboard.

Thanks!