Another problem. If I stack three clips -- track 1, track 2, and track 3 -- and then do an affine transition between track 1 and 3, it doesn't work. For some reason, track 2 shows instead.

Sigh. Help...anyone...please...help me...

Its just an ordering issue. Think if it this way. When you composite between 1 and 3, then track 1 is married to track 3. Track 2 is now on top.

What happens if you try either of these?
1) Add composite to track 2 and connect it with track BLACK
2) Add a composite to track 2, connect it to track 3, and change the opacity to 0%

I just tried both of these and they worked for me.

smokinglizard wrote:Another problem. If I stack three clips -- track 1, track 2, and track 3 -- and then do an affine transition between track 1 and 3, it doesn't work. For some reason, track 2 shows instead.

Are transitions connected to proper tracks? Not "automatic" but "video 1", "video 2", etc.?

Transitions are created on a given track.
One of the properties of that transition is "Which track to interact with"
The default for this option is Auto. But you can override it to pick a specific track, or even the implied hidden track "Black"

stevej wrote:..., or even the implied hidden track "Black"

I still struggle with the transition model from time to time even after working with kdenlive for two years, so where is the implied hidden black track located within the track hierarchy? Bottommost track?

TheDiveO wrote:where is the implied hidden black track located within the track hierarchy? Bottommost track?

When you select the composite on your timeline, at the top of its details window (Transition) is:
1) TYPE
and
2) WITH TRACK

With Track defaults to auto, but you can choose the drop-down menu and define a specific track. At the bottom of the list is "Black". This is not a track you manage with a Black color clip on it. It is a free gift. I don't use it myself, but I think of it as an option of last resort for MLT. If you put a transition on your bottom track, what will WITH TRACK-auto use? I believe Black.

I'm sure but there must be other use cases for it, but as I said, I just create a track for color and then put whatever color I want on it.

As for hierarchy, it goes from top to bottom on the timeline. Things don't get odd until you have 3 or more video tracks. One trick is to composite all tracks to the same base one. Sometimes this trick won't give the results you need though. It really depends on what you are doing and what you want. Window in window + scaling + keyframe motion come to mind as the type of things that will make you think.