One effect across multiple clips?

Hi -- a few people on the IMUG list pointed me here for further help. Looks like a good forum. I'll try to be brief but it's a complex question...

I'm using M100i, xr, version 7, and Boris Red 5.something. Need to create an effect where a chromakey background clip changes underneath a continuous overlay clip. Timing is essential -- it's a transition from a still frame into smooth motion, cued by a particular action on the overlay track. I did it, but in a rather nightmarish way that I don't want to go into...

I got some good advice, from a user of an older version, about an easier way to do this. As I understood it, you need to

1)first create the transition of the desired length, regardless of the length of the desired video sources (slugging in black if needed).

2)Then select the Movie Files I want for the actual tracks.

3)Then, since Boris WILL assume you want the clip to start at the start of the Boris timeline, the advice was to offset the Start Time of the Movie clip used for the second background clip, and offset the Clip Head since the older Boris won't recognize my clip in point.

OK. But then, someone says that with Media100i, I could just create a container track for the whole duration, and add the clips from the Bin Browser at the appropriate timings, creating a second track for ChromaKey background 2.

Again, OK. Importing clips from the bin broswer does retain the in point I set in M100. Cool. And I can drag the last keyframe of the chroma background 1 track back, and the first keyframe of my chroma background 2 track ahead in the timeline so that the background changes from 1 to 2 just where I want it to.

*** BUT...!!! every time I do that, it also changes the in point of the chroma background 2 clip, so it doesn't match the freezeframe on the other background track anymore. I can't even work around this by cheating if I wanted to -- the second clip only has a couple of seconds at the head of it; not enough to wait in the wings until it is time for its grand appearance. So trimming it back in M100 by the required amount isn't an option (plus that's more annoying manual calculation again)

Is there an easier way to do this with M100i v.7 and Boris 5? I understand the RED 2 will have slip and slide... that's great, but how can I work this for now? Is there a way in Boris to say "start this track here" and have it use the first frame of the referenced clip?

Thanks!

--Scratch

thanks, that helped! Now, onward...