摘自DVD2one網站:
DVD2one V1.2.0
Here's a new version of DVD2one with the following new features:
New engine with constant compression ratio for better image quality in long movies (2 1/2 hours and more).
1.2.0版才加入constant compression ratio的選項.

In general the constant ratio mode works better on long (2 1/2 hours and more) movies than the variable mode, because excesses in compression ratio will be more visible at lower bit rates.
按照作者的意思,因為超過兩個半鐘頭的影片流量一定很低,
所以使用Constant Ratio會採用固定的再壓縮比,(這由Bitrate的圖形可以看得出來)
而若是使用Variable Ratio時就有可能將低流量的部份再壓縮到更低,
這會使得畫質損失的較為嚴重,