Do NOT use the LP-mode.
- Anyway, I do not think you can play LP footage in SP mode. That is, the effect is not fast motion- if that is what you want to achieve.
The better way is to use the timelaps-mode in the camera (if your XL-1 has such an option. Or you can just record the sunrise as usual, and the speed it up in Post.
One option in such timelaps, is to (in post) devide the screen into to parts (still whipe - soft) and let the lower part go normal speed, and the upper part of the picture go timelapsed or fastmotion. -Maybe not for your shot, as you have the change of light becau