Suddenly the file was too small

I've used GKnot for months and it has always delivered the right filesize. But I encoded "Signs" the other day, and the file came out with a size of 650 Mb, instead of the normal 717-719. The quality was very good, though. Is there an answer to this?

Maybe. What version of GKnot do you use, what result did the compression test give and are you using the correct version of DivX for your GKnot?

Sounds saturated, what was your first pass file size?

I Use DivX 5.02 GKnot 0.27.0.13 The compression test showed 87.9 (!) The credits tail was many minutes long. I don't know how you find the first pass file size.

Well, the file was already 608 x 320 px, so if I should have increased the resolution, I would have been forced to enlarge the picture.

I encoded that same movie about a week ago. Even with a resolution of 640x352 I got a 1st pass size of 1 GB and a compressibility test of 75% (no B-frames). So it's definately a compressible movie. Encoding at 87% like you did is overkill and more importantly, DivX 5 has problems with reaching the target filesize when going over 80%.