Right then I have this disc which has the film and the audio dubbed in English and the original audio in Thai. It also has the option to turn subtitles on and off. It is on a dual layer disc, just under 8gb of data. I want to copy it to a 4.7gb dvd-r. CloneDVD will not compress and copy the whole disc to one 4.7gb because the video quality goes under 50%.
If I choose to copy 'Main movie' then it copies it fine but with the English dubbed audio. I'm only intrested in the Thai audio and the subtitles. So I figure that the if I can find out which files these are and select only them it will fit onto my disk. Tricky.
Edit - I've got this information using IFOedit