Okay, I'll take a stab at it, based on just now playing around with these features for a little bit. So, class, everybody open up VMS and make a little "test" project that you can play with. Grab a couple of still photos or short video clips, and experiment.

Track Motion: First of all, I thought this seemed to be about the same as pan/crop, except that it operates in a more natural way than pan/crop. To make your image smaller, you actually drag a corner of it to make the video image smaller. (On pan/crop, the video image stays the same size, and you drag the frame outline bigger in order to make the video image smaller.) Also, you can drag the image around to affect its placement.

The full version of Vegas gives you 3-D track motion, which lets you rotate the video image in 3-dimensional space (can tumble and spin, make it slide in flat, etc.) We only get 2-D track motion in VMS. So I was wondering what track motion offered over what we can already do with pan/crop. It finally occured to me that one big advantage is that Track Motion lets you work with multiple events, treating them as one entity.

You get keyframes with track motion, just as with pan/crop, so you can leave your track video "normal" where necessary, and apply keyframed motion just where you so desire.

The easiest example is a "picture in picture" effect. With pan crop, you could easily have two tracks, with the lower track acting as a full size background, and the upper track shrunk down to be a picture-in-picture. You can also easily have that p-i-p move, say from the top right side of the screen to the lower right side of the screen.

Follow me so far? Simple enough to do that with normal pan/crop right? Well the problem with pan/crop is when you want several consecutive items in the p-i-p (picture-in-picture). Could be three or four still photos, or video clips, or whatever, but you want this video to move as a p-i-p from the top right to the bottom right. You *could* do this with pan/crop, but it would be cumbersome. Pan/crop only applies to a single event, so you could have the first picture move partway down the screen, then copy those x-y and size settings for the starting point of the second picture, etc. It could be done, but wouldn't be much fun.

Also, as Chienworks pointed out in a recent post, if you are using pan/crop to zoom in and crop a still photo, then you can't also be using it to "zoom out" to do a picture-in-picture. Only one or the other.

So here's where track motion comes in. It operates with the video track, not just a single event, so you can have multiple video clips or photos all controlled by a single, convenient motion control. Your photo sequence with all the crossfades, etc., can easily be used to make a picture-in-picture effect. Create your video as normal, then apply track motion, and your video -- multiple clips -- will play back as a single, moving, picture-in-picture.

Parent-Child Motion Okay, now that we understand the "track motion" thing, what is Parent-Child Motion? I didn't notice it at first, but when you click on the icon to "Make Compositing Child", you get a new pair of icons at the left edge of the "parent" track. These are the "Parent Motion" and "Parent Compositing Mode" icons.

For example, assume tracks #1 and #2 are to be made into a Parent-Child relationship. Go to track #2, and click the "Make Compositing Child" icon. It looks like a pale blue stip with a dark blue arrow (initially pointing down), and is the last icon on the second row in the track header. When you click this icon on track #2, the arrow changes to pointing up, which indicates track #2 is now a child of the track above it (track #1). Also note that the front of the track header for #2 is now indented. And now above the indented area of the header (just below the minimize and maximize buttons of track #1) are two new icons, though they look the same as the normal "Track Motion" and "Compositing Mode" icons. However, these two new icons work on the combined result of tracks #1 and #2.

Consider the picture-in-picture example above, which we accomplished with "Track Motion". Now assume that we wanted to overlay titles in the picture-in-picture. Just to visualize something, imagine that the p-i-p video is a sequence of still photos of a kids baseball team, and you want to put their name with each photo.

You could to that by having a separate title track, and applying track motion to that track, and making it exactly match the track motion settings of the video (photos) track. In effect, the titles would just be doing the same track motion as the picture in picture, so it looks like they're moving together. But again, meticulously duplicating motion settings wouldn't be much fun.

So instead, use parent child motion. Put your titles on track #1, and your photos on track #2. Make #2 a "child" of track #1, then use the Parent Motion (near the left edge of the track header) to shrink the "composited" (combined) tracks down and do the motion, picture-in-picture.

Now I'm sure their are a lot of other uses of the parent-child thing, but I expect this is a good starting point. Basically, when you want to combine two or more tracks, then shrink (or zoom) the result, use Parent Motion. You could also do picture-in-picture-in-picture, for example. Or maybe some green-screen work, where two scenes are combined, then shrunk down together to fit the scale of a CGI background, etc. Or, a green-screen shot with an actor, and a "child" track of the background, and then use Parent Motion to zoom in or pan, etc., so that the zoom/pan is doing actor and background exactly the same.

Okay, class dismissed. But all further discussion is certainly welcome.

Tim L