Hi John, thanks for your answer.  How are you "trying it out," when you do not have stereoscopic footage?

Here's how you can simulate my problem.  Take any clip you have, duplicate it into two channels, synchronized one atop the other (eg channels 1 and 2).  Select both and make them into a stereo3d object (effects>stereo3d>properties>"stereo3d pair (left image first)).  This makes for a very "flat" stereo object, but it will be a stereo object nonetheless, in which you can change the stereo parameters.

Do this with the monitor set to "anaglyph", if you want to see what's happening in 3d - you'll need those red/blue lenses glasses - find them at any comic book store.

Now you can go to the alignment and keyframe different values for horizontal alignment.  (you can of course keyframe any of the values, but 99.9% of the time, only horizontal values will need keyframing in a stereoscopic production).  Now as you get to higher values, you should see cropping.  As you return to lesser values, the cropping does not go away (anyway, that's my problem.  Nice if you could duplicate it.).

Would you mind testing this for me?  I'd thank you a lot!

I can get 3D footage from friends who do have 3D cameras and or are using two 2D cameras on tripods set for 3D capture. I also can use the demo footage that came with the Movie Edit Pro for 3D.

I will start testing this to see if I can duplicate and get an exact understanding to what you are doing. I appreciate your time with me on this greatly.

Is this what you are referring to:

I am not sure you can see that very well... but I am getting some cropping borders that even though I set back to zero still show. Now, I can reset them using the double arrow >< that is found near the top of the settings area for alignment.

Using the reset though will change all the settings that have been made for that object that are dealing with the 3D stereo Alignment. I am not sure that is something you would desire, but that reset eliminates the cropped borders.

I am not sure how to correct this other than maybe doing a possible camera zoom after the alignment is done. 

Hello John, thanks again for bearing with me on this.  You seem to have a lot of experience with MEP, and I don’t, so I hope you can teach me about MEP, and in return maybe I can teach you some stereo3D!

You’re screengrabs do not show the cropping problem that I am seeing.  Maybe you need to give larger horizontal shift values.  I do see that you’re anaglyph display mode is set to “blue filter on left eye” or the stereo3d is backwards for USA users, anyway.  (In Europe, some anaglyphs are published red/right.  In USA all anaglyphs are published red/left.)  I might be wrong about your display method also because I don’t see a lot of depth in the screengrabbed anaglyph.  Is it a stereoscopic picture, or did you grab a flat image and do the simulation I suggested?

Here is what a normal, well aligned 3d image looks like, in anaglyph red/left (“well aligned” except for the handlebars, which “violate” the screen/window - i.e. appear in front of the screen).  My horizontal alignment value is -2.0.

No matter, You’ve motivated me to look into my cropping problem some more, and so I have a few more observations to report.

First of all, I noticed now that the crop is on the right eye image only, on both the left and right sides.  Before, I had thought that MEP was giving me a so-called “floating window,” which is something that is useful for extreme horizontal shifts in the stereo, to minimize the visual  “window violations.”  Floating windows essentially shift the apparent screen plane forwards towards the viewer, i.e. off/above the actual physical diplay screen.

Such a stereo window - a “floating window” - is created by cropping the right eye on the right side, and the left eye on the left side, by bringing a black border in on those respective sides.  When I first saw MEP doing the cropping, I assumed that’s what it was doing.  In fact, that is what it is doing, but only on the right side image.  MEP is cropping _both_ the left and right edges of the right eye image.  The left side of the image is completely screwed up, because the left edge crop should be getting done on the left eye, not on the right eye image.  You can verify this with your anaglyph glasses on my screengrabs:

(notice this is a very close up handlebar, needing significant horizontal alignment shift to put it near the screen plane.  You can see that the brick wall, not far away, is showing a stereoscopic separation comparable to "infinity" on the first screen shot.  You have to keep infinity points within certain limits.  I'm lucky that there's no true infinity in this very close up shot.).

So this is an even more severe problem than I first thought, because these crops that MEP is giving me are completely useless, and I’ll have to work around them by zooming into the image (if possible).

The other thing I observed was that although the horizontal alignment (called horizontal image translation, or HIT, in some 3DTV circles), can be animated to various values, the cropping is based on whatever the largest alignment adjustment value is, and that cropping is applied to the entire clip.  In other words, the cropping does not animate along with the variable HIT adjustment.  The ideal implementation of cropping would recognize the need to properly, separately crop the left and right eye images, and would animate, so that cropping would be applied only where needed.

(here now we're getting some distant far points, so the HIT has to be reduced, bringing the handlebars "closer" to you.  Notice though that although the HIT = -4 here, the alignment of far points is more like the first screen grab, which has a HIT of -2).         

One final thing I observed is that after cropping has been invoked by MEP, the HIT values I enter are not producing an absolute shift anymore.  The shift appears to be relative to the right edge crop point.  This is all very confusing and irritating - it’s difficult to figure out a workaround for this.  It seems that the horizontal adjustment becomes pretty much useless above certain values, which means that some shots with extreme alignment needs simply cannot be used.

(Here, my values are back to "normal," with a HIT of about -2.0, just like in the first screen grab above.  But you can see this shot is screwed up: the horizontal alignment is nothing like the first  screen grab.  Not sure why MEP is rendering this shot this way.  It seems to be using the right side crop as a reference point, now, instead of the actual screen plane.)

THanks for pointing out the reset button!

Boris

PS

I'm launching a few more questions under a different heading.  Hoping you can help us.

Hey John, I studied this some more today, and learned some interesting things.

MEP puts the stereo alignments on the left and right video tracks individually and separately.   I hadn't realized this before.  I'm spoiled by some other stereo image processing software (StereoPhotoMaker - for stills), and had made an assumption that MEP works the same way.  In SPM, when you adjust a stereo parameter, say rotation, it will apply equal and opposite rotations to the left and right images.  MEP does not do that.  (Note to magix, it would be nice to have coordinated stereo transformations, as an option).

So it's just a little bit more work now, but it does work properly for me.  The cropping problem was the result of me doing my stereo adjustment (horizontal shift primarily) on just the one eye (the left eye image).  Now I can go through a given stereo shot and just make sure to adjust both the left and right eye tracks (inputting equal and opposite sign values).  Instead of adjusting the left track only to HIT = -2, I now adjust the left to -1, and the right to +1.  The video looks good and all is well.

THanks for your input, which helped me to discover these "features."

Boris