Secret for using Cross Dissolve transitions

Question

Based on my limited experience, the most useful transition is the cross dissolve. It is pretty much the only one I use since it is doesn't draw attention to itself and bears repeated deployment for smooth scene changes. But it has a problem: If you simply make a clip split and put the transition in, it won't work. And it appears even high level people at Apple technical support don't understand what is going on. Based on the apparently incorrect background information they gave me, I have always been extremely careful about making the split precisely where the scene changes and then chopping off a small number of frames in order to make the transition work. But recently I discovered that cross dissolve transitions will always work (regardless of whether the frames on both sides of the cut are similar or even identical) if you delete precisely one frame, and it can be from either side of the split. When you do that the edges of the clip go from squared (right angles) to rounded. The cross dissolve transitions will never work between two clips that have squared edges. They will always work when the edges are rounded. And all it takes to get the edges to be rounded is the deletion one frame. The edges get rounded and cross dissolve transitions work and if you remove more than one frame, and/or do if from both sides of the split. The point is that it will work with as little as one frame. But if you don't sacrifice at least one frame, cross dissolve transitions will never work.
Of course, I am assuming that my experience with iMovie '09 and '11 is not idiosyncratic. Also: I would be interested in knowing if anybody else knew this "secret"--and whether it is widespread knowledge or in any of the books on iMovie.

Answer 1

When one splits clips, don't split close to what will be the beginning or the end of a shot.That's why you should always start the camera BEFORE the action begins and run AFTER the action ends. It only needs to be a 1/2 second to 1 second. Now before you add a cut or a transition you will automatically trim the end and the beginning of the two clips.
I start with a two-hour clip that includes hundreds of scenes, some ending abruptly, some not. If scene one suddenly ends and scene two begins, the natural place to make the cut is where the scene changes. If it happens that there is stuff immediately on each side of the cut that is of value, you would might prefer not to lose even one frame. Usually on one of the two sides the loss of one frame is not so bad. And if you sacrifice that frame you have almost everything you want. But it turns out that the situation is better than that. Since you can also add frames (I now realize), you can end without losing any frames at all. Of course, if you happen to be in a situation where there is plenty of useless stuff on both sides of a cut, the problem the solution is trying to solve does not come up. But I wouldn't change my filming habits just to avoid this problem of adding cross dissolves, since once you know what to handle it, it's not much of a problem. As to whether it is good practice to aim to have extra footage on both sides of a shot, sure. That seems like a good rule of thumb to me. But there are many situations where you don't have that opportunity. Say you were filming John Kennedy in Dallas or life among the Taliban or your kid falling off a horse. Life may not give you the chance to put useless footage at the end or beginning of your shot. In my case, I have hours of amateur home movies that stop at all sorts of odd places. I can't go back and reshoot it.
I suspect Apple simply expected you to do this. This will inherently eliminate what may be a tiny bug that you overcome by trimming 1 frame.
Most transition types don't require the removal or addition of a frame. When I called Apple technical support about this, the person I talked to was surprised by this feature too. And he found it happening with at least one other transition, I think. He handed me over to a specialist. That specialist gave me a complicated theory for why this was happening. He said that the frames on both sides of the cut had to look fairly different for the transition to work. And sometimes when we think we have made the cut exactly where the scene changes, we haven't in fact. So we need to cut away until both sides are definitely different. And you will notice that often the thumbnail for one side will be an image from the other side. This lead me to think that I was required to make sure that on either side of the cut there was definitely a significant change of image. But all you have to do is get the edges of the clip to become rounded. And you can do this by adding or subtracting a frame at any location. Of course, if you are going to be chopping off multiple frames for any reason, you will also solve or avoid this problem. So, if Apple was thinking what you suggest, they haven't given any guidance about it in print. And the tech support people don't seem to know it.
Message was edited by: Paul Bullen