Nero? File too big? still burn...?

im burning a MPEG-4 into VCD. im using Nero. Although according to the file size bar, its ays that my some part of my file wont fit into the disc. When i press burn. It still encodes and now on its way to burn. It doesnt show any error. Is it going to compress my video or is it going to ask me for another disc when the space runs out? or is it just going to terminate the process when it finds out that my disc can no more upload?