Make DVD read only.

[Cry]

On retail DVD's, you can only read but not write, They are always full to capacity.

I'm burning a home movie ISO (2gb) to a dvd (4gb), And I can always still add files to the DVD after the burning, does my ISO have to be 4GB.

[manono]

On retail DVD's, you can only read but not write, They are always full to capacity.

No, they're not.

...does my ISO have to be 4GB.

No.

I'm burning a home movie ISO (2gb) to a dvd (4gb), And I can always still add files to the DVD after the burning...

Either that's incorrect or your DVDs aren't being finalized. Use ImgBurn to burn to disk.

[betwixt]

Provided you are not using rewritable discs and you finalize them, nothing more can be written to them, even if there is remaining space.
There are applications which allow more to be added to rewritable discs, they read the original contents, erase the disc then write it back with the added files so it all takes place in one write session. You can't do that on normal DVD+R or DVD-R discs though, only rewritable ones.

Brian.

[Cry]

Thanks manono and betwixt, your reply's have been very helpful!

[usually_quiet]

Provided you are not using rewritable discs and you finalize them, nothing more can be written to them, even if there is remaining space.
There are applications which allow more to be added to rewritable discs, they read the original contents, erase the disc then write it back with the added files so it all takes place in one write session. You can't do that on normal DVD+R or DVD-R discs though, only rewritable ones.

Brian.

The scenario described above can be done manually, without any special software. I have done so many times. Re-writable DVD media is designed to be erased and re-used.

However, creating actual multi-session discs, which can be done with a program like CDBurnerXP or Nero using write-once DVD media, is discouraged by most members here because reading such discs is often problematic, especially using a different PC. That is because multi-session discs are left open (not finalized) after each session.