question about total file size of DVD main movie and how to back up

[jimdagys]

I have a DVD movie that is almost 2 hours that I want to back up. I used DVD Fab Platinum and choose to back up just the main movie. However the quality factor shown is shown to be about 68%. I don't understand that because I thought a 2 hour movie would always have a quality factor of near 100%. In other words, I thought a 2 hour movie would never need any shrinking to fit on a 4.3 GB disk. Then I looked at the VOB files and see about 6GB of video just for the main movie. How can a 2 hour movie have 6GB file size?
What is the best plan to back up this movie? Should I just go ahead and back it up with a quality factor of 68%, or should I try a different approach? I want the movie to fit on one 4.3GB disk.

[redwudz]

I would use DVD Rebuilder in this case. It will take a while, but if you want the best quality for a larger movie to a DVD-5 conversion, it would be my recommendation.

[Baldrick]

Many 2 hours movies are bigger than 4.38GB. You could try and shrink and see how it looks like and if it's too crappy maybe try use dvd-rebuilder instead.

[jimdagys]

You said, "Many 2 hours movies are bigger than 4.38GB."
Thanks for the reply. I am trying to understand an important point. I thought with store bought DVDs, a given length of movie always translated into a given file size. ( In other words, I thought a 2 hour movie always was less than 4.3GB.) Apparently I am wrong. So DVD is like mp3 music ( can have different bit rate, and therefore different file size)? Then, when you buy a DVD, how can you know (before you actually purchase it) what is the bit rate (file size per given length)? Is it worth trying to buy a DVD with higher bit rate?

[guns1inger]

You cannot know before you buy what bitrate has been used. Generally dual layer discs use a higher bitrate because they have the extra space, however many films released on dual layer discs end up being smaller than 4.38GB once the extras and secondary languages are removed.

[jagabo]

I thought with store bought DVDs, a given length of movie always translated into a given file size. ( In other words, I thought a 2 hour movie always was less than 4.3GB.) Apparently I am wrong. So DVD is like mp3 music ( can have different bit rate, and therefore different file size)?

Yes. DVDs can use different bitrates. A 2 hour movie will usually be on a dual layer disc and will be over 4.3 GB.

[ntscuser]

You said, "Many 2 hours movies are bigger than 4.38GB."
Thanks for the reply. I am trying to understand an important point. I thought with store bought DVDs, a given length of movie always translated into a given file size. ( In other words, I thought a 2 hour movie always was less than 4.3GB.) Apparently I am wrong. So DVD is like mp3 music ( can have different bit rate, and therefore different file size)? Then, when you buy a DVD, how can you know (before you actually purchase it) what is the bit rate (file size per given length)? Is it worth trying to buy a DVD with higher bit rate?

Columbia Tri-Star obviously think so, their so-called "Superbit Collection" routinely spreads a basic movie over as much of the dual layers as possible.