TMPGEnc transcoded file size

[EnemyWithin]

I tried using rempeg2 to transcode Alien, but the result was terrible. So, I decided to try it with TMPGEnc. The average bitrate (according to rempeg2) was around 6240000 bps, and using the DVD-R calc, I knew I needed to shrink it to about 76% (or to about 4700000 bps). So I setup TMPGEnc for a 2 pass VBR with the average bitrate at 4700 kbps (max 9500 kbps, min 0 kbps). This resulted in a nice quality file that was 5.7 GB. The original VOB's with audio were only 5.5GB!

So, I tried lowering the average bitrate to 3700 kbps as a test. The quality definately got worse (noticable pixelation now), but the file size stayed almost exactly the same. It actually got slightly larger!

All the settings are used from the TMPGEnc tutorial at doom9. Beside the file size, the resulting file is perfect (plays smoothly and is the correct aspect ratio). What am I doing wrong?

[EnemyWithin]

I finally managed to get a good quality .m2v transcode from TMPGEnc by using CQ-VBR at quality 35. This resulted in a ~3.95 GB file.

I am still confused by the results I was getting with 2-pass VBR though. Can anyone shed any light on using TMPGEnc 2-pass VBR and the average bitrate setting? From my experiences with Alien, it seems that the average bitrate setting has very little to do with the final results.