I'm trying to burn 4-5gb .mov files (about 2 hrs long each) to 25gb blu-ray discs. At first, I put about 18gb of files onto one project and Toast showed remaining space. It encoded for hours, then gave me an error that the project didn't fit by a few megabytes... So I removed the files off the project one by one, until I had ONE file that was taking up 16gb on the disc. Why is Toast blowing up a 4gb file to 16gb? I thought a 4gb file should take up exactly 4gb of space on the disc.