Why can't I record a 2-hour video to DVD?
The most common reason that your video will not burn to a DVD is because it is too long. When videos are originally created there are many possible bit rates that may be selected by the author. These bit rates affect the size of the video as well as the quality of the video. A higher bit rate will have a higher quality video but will also produce a much larger file size.
Here is the technical explanation of how data is stored on your PC and the actual amount of data that a DVD can hold:
Blank DVD-R discs hold 4.7GB of data. However, this is when you define 1 GB as 1 billion bytes. Computers define a GB as 2^30 = 1,073,741,824 bytes. So, a blank DVD-R disc really holds only 4.377 GB, or slightly less than two hours.