A 6.4gb hard drive will not be enough for most disc burning. The typical type of burning will require you to rip the Video TS files to your hard drive, then you will weed out what you don't want to put on a standard DVD 5 disc. The reason this is done is because most retail DVD's are 8gb+, thus being DVD9's, while the cheap blank dvd's you buy at the store are DVD5's(4+gb).
Yes the DVD 9's are available in a blank media format, but it requires having a dual layer burner. Basically it just makes the entire process more expensive and if all your doing is backing up videos, it's probably not worth it.
Second scenario is the fact that you simply compress the 8GB down to fit on a DVD5, the resolution will be so terrible it will see like VHS. Therefore, you would be required to rip the files to your HD, take out the extras, and at times you won't need to compress at all to fit the movie 'only' onto a DVD5 disc.
Hope this makes sense, if it doesn't you are welcome to send me a PM.
Edit* Damn Zap, you beat me to the post button.
