It wasn't until this year that I started playing around with integrating video effects into my trailers. And while doing that I learned a valuable lesson, which I'm going to share with those who are doing it or are thinking about doing it.
If you're downloading and/or converting a video effect and using moviemaker or Sony Platinum, use the SD version and not the HD version of the video. Simply put, it's because SD can be played on anything, including HD players, but this isn't always necessarily true the other way around.
Case in point, check out my video transitions in my trailer "Sleepless". Stilted, to say the least. This is when I realized SD works much much better, hence why my "Dark Divine" runs so smoothly.
Hope this helps anyone out there!!