Time Machine Not Recognising Changes

[A Macbook Pro]

Hi guys, I just imported 20GB of HD video from my iPhone 4. But before I delete it, I want to make sure it's backed up, but it seems my Time Machine backup won't take note of the changes to my HDD. It just backs up a few KB and acts like my backup is up to date, when in reality it isn't. I've done a eject, restart, and verify disk to no avail. I'll be pissed if I have to start my backup fresh again as it isn't the first time.

Thanks in advance.

 

[kostia]

Im grasping at straws here, but this is what occurs to me.

Is it in a folder that's excluded from backup in the Time Machine settings?

Do the video files have generic/default names that might match filenames stored elsewhere in Time Machine? Try giving them new unique names.

Or it could be backing up and you just aren't seeing it for some reason. Copy a video file to a second location, run the Time Machine backup, then delete this second copy of the video and empty the trash. Then launch Time Machine from that location. Does it offer you the ability to restore the video file you just deleted?