2 hr clip->vbr encode (4500 avg)->4.7gb file. why?

[jlietz]

Please someone correct me if I'm wrong, but when you use VBR isn't the file size supposed to be predictable? I've been using Procoder 2.0 and have several videos that are 2 hours long, give or take 3 minutes. I encoded them with 2-pass VBR (avg. 4500, min 100, max 8000). Files sizes were:
1) 4,781,474 kb (2 hrs)
2) 4,203,616 kb (2 hrs 3 min)
3) 4,756,796 kb (2 hrs 3 min)
According to the videohelp.com bitrate calculator I should have had enough room to fit 2 hrs 3 min on one DVD at the specified conversion settings with bitrate to spare. What am I not getting? Or is Procoder ****ing with me?
On a side note, I'm really getting frustrated with Procoder 2.0 (bugs, conversion crashes, never recognizes whether my input file is interlaced, etc...)

[jimmalenko]

What are your audio bitrates ?

[jlietz]

I demuxed the files, so the size I've posted is video only. FWIW, I originally enocoded to PCM audio. DVD Workshop 2 will handle the AC3 (256 kb/s) conversion for me.