I'm looking for a tool that supports editing subtitles as a track along with the video and sound. I want to be able to slide the subtitle left or right in relation to the video frames. I have FCPx but it's my understanding that the subtitle track is not "real" as in it can't be turned on and off. I have ISubtitle. It lets me view one frame at a time. The same with many of the subtitle tools. Is there a better non-linear video editor?