Likewise if your internal hard drive is getting to small for your movie, photo and music collections, then you could move and store any or all of them on a good external hard drive.
What application are you importing your video into? iMovie? Final Cut? Depending on the original file format, it may have been automatically changed to one that the application can read - in that case, the file might have gotten larger. For instance, a song in MP3 format is quite small; if you convert it to AIFF format, it suddenly balloons to 40+ MB. The same thing may be happening with video.
Second, as denthed has mentioned, you do not have enough space on your hard drive. If you want to edit/render/burn video, you will need at least as much empty space as the combined size of all your files is in order for the computer to be able to work with the video reasonably efficiently. During my last project, I amassed a total of 130 GB of various files and made sure I had at least that much available - personally, I prefer more, so I had over 200 GB empty. When I was done, I deleted all the files and simply moved a .dmg of the movie to an external for possible future burning.
If you do not work with video, your OS still needs an absolute minimum of 10 - 15 GB of empty space at all times in order to run.
Hard drive getting full or near full?
Here are some of my tips for deleting or archiving data off of your internal hard drive.
You'll need to free up lots of hard drive space.
At a minimum, at least, 15 to 20 GBs of space.
Perhaps even more.
Hard drive full or near full:
Have you emptied your iMac's Trash icon in the Dock?
If you use iPhoto, iPhoto has its own trash that needs to be emptied, also.
If you use Apple Mail app, Apple Mail also has its own trash area that needs to be emptied, too!
Other things you can do to gain space.
Delete any old or no longer needed emails and/or archive older emails you want to save to disc, Flash drive/s or to ext. hard drive.
Look through your Documents folder and delete any type of old useless type files like "Read Me" type files.
Again, archive to disc, Flash drive or ext. hard drive and/or delete any old documents you no longer use or immediately need.
Uninstall apps that you no longer use. If the app has a dedicated uninstaller, use it to completely uninstall the app. If the app has no uninstaller, then just drag it to the OS X Trash icon and empty the Trash.
Also, if you save old downloaded .dmg application installer files, you can either archive and delete these or just delete the ones you think you'll never install, again.
Download an app called OnyX for your version of OS X.
When you install and launch it, let it do its thing initially, then go to the cleaning and maintenance tabs and run all of the processes in the tabs. Let OnyX clean out all web browser cache files, web browser histories, system cache files, delete old error log files.
Typically, iTunes and iPhoto libraries are the biggest users of HD space.
If you have any other large folders of personal data or projects, these should be thinned out, moved, also, to the external hard drive and then either archived to disc, Flash drive or ext. hard drive and/or deleted off your internal hard drive.
You may have to Purchase an external FireWire or Thunderbolt hard drive to move these files/data off of your internal drive to the external hard drive and deleted off of the internal hard drive.
Not familiar with either the camera or the software, so I'm not sure what it does as far as conversions, etc. I take it that is all you use - not iMovie or other Apple/Mac apps? I've also never used anything to get my footage to the computer - I just plug in my card reader and drag the footage off the SDHC card.
The camera is a HD compact video recorder that is made to put into small places, or on your head (for POV). I would use iMovie '09, but mine isn't working. Click here to see the problem that I'm having. Maybe you can help!