My problem is when the play goes across the middle. I need to move the frame from one side of the screen to the other on back-to-back frames keeping the current level of zoom. I do this by placing a keyframe on one frame, advance to the next frame, and drag the zoom over to the other side of the screen. However... This doesn't work if I only advance one frame. It doesn't place a new keyframe, but rather just changes the previous one. So.. my workaround has been to advance two frames, move the zoomed view, (it does create the second keyframe) then choose the new keyframe and move it back one frame. As you might imagine, when the play crosses the middle 60 to 80 times in a 70 minute match, this makes editing take a LOT longer.
Please confirm the version of VPX that you are using.
I'm having trouble visualizing what you are doing with the keyframes/zooming. When the play crosses the middle, then you had a cut there to the other camera, correct?
What do you mean by drag the zoom in "I do this by placing a keyframe on one frame, advance to the next frame, and drag the zoom over to the other side of the screen?" You can't drag the zoom, only the image in the preview monitor, I think.
Can you give us a more detailed description of what you are trying to do, along with some relevant screen shots?
Are you trying to zoom in on the second part when the play crosses centre field keeping the play showing by dragging the zoomed image to the left or right depending on which way the play is going?
Did you try cutting the video object at the point where the camera changes occur and then applying the keyframes to each object?
Why don't you do this with the original timeline with all of the already cut clips? Just turn off multi-cam.
Why did you export to mp4 and not mxv, the Magix format, which would likely run much smoother? I would still stay with the original and edit there. The cuts are all there. The only reason I would export to an intermediate would be if effects got too heavy for smooth editing, for example, when using Neat Video.