HOw to compress a folder from 8.8Gb to 4.5 Gb?

[topman13]

Hey, im new to this dvd recording.

Basically i want to record this tv series which has 27 episodes. I would like them to fit on 2 discs; so 14 on one disc and 13 on the other.

They are all avi files. So first i used winavi video converter to convert the first 14 episodes to vob format with .bup and .ifo files.
The size of this folder is over 8Gb but i want to sompress it so it fits onto one disc.
I read that you had to create an image file and then use DVD shrink to compress it. So using IMGtools, i made a .nrg imag file. However i cannot open this in DVD shrink. It says;

DVDShrink encountered an error and cannot continue. Failed to open the file

I do not know what to do next and i was wondering if anyone knows how i can compres that folder so i can use Nero Express to burn it?

[Baldrick]

just click on open files in dvdshrink and select the video_ts folder(the folder with the .ifo .bup .vob files).

[topman13]

It says invalid data in the vob file, when i do that!

The image file i have created using Imgtools was under 4.5 Gb so it would fit on a disc, but do you know how i can get it onto nerovision express2 so i can create chapters and menus?

Also, is there anyway i can import the .ifo and .vob files in nerovision express 2 because there is a lot of time taken on transcoding