how to burn five films in one 4.7GB DVD?

Answer 1

I hope you don't want to put five 1.5 hr movies into one DVD, because the quality will be terrible.

All compressed films have a bit rate. For example, typical DVDs are made at a bit rate of 6 Mbits/s.
Divx (at DVD quality) can be as low as 2 Mbits/s.
Movies at VCR quality can be as low as 500 kbits/s.

Your bit rate defines how long a video you can fit into your DVD.
Don't forget audio, which is usually around 128 kbits/s.

So, lets say you have five films, 5 hours total. To fit it in your DVD you need to use a bit rate b Mbit /s of

((5*60*60) * b )/8 = 4,700 -> b = 2.09 Mbits/s (video+audio)

If it is 10 hours total, b= 1.04 Mbits/s

You get the idea.