It all depends on the codec the file uses, Karli.
What model of camcorder is this video coming from?
Are you working on a Mac or a PC? Have you got the latest version of Quicktime, per the program requirements? When you started your project, did you select the settings for a DSLR at 720p? This is a vital step since it will activate the components your computer will need to work with many of these types of files.
BY THE WAY, KARLI--
PLEASE do not post the same question more than once on this forum! You've already got a thread going with this same question and several responses posted. It's very confusing when you post the same question a second time and start a whole new discussion.