I have a DVD image about 1.4 GB. Is it possible to burn this onto a DVD-r, then somehow keep the disc open and use the remaining space to burn an AVI file as a data file?
No.... regardless of how small the file is i.e. 1.4gb or 2.8gb when you're burning it into a DVD-R disc, once it's done it won't let you re-write again, it will just pop out right away. Yes..... if you're burning your DVD image and your other AVI files as "data" at once, then you can use "Nero" to burn as much as possible or whatever your DVD-R can hold them.