DVD Shrink Compression-Please help!!

[Jonathan]

I just have a few short questions that I hope someone can answer:

1. Is there an ideal "target" compression threshold of like 70 or 80%? At what point does it noticably affect your picture quality?

2. Why do movies of the same length result in different compression settings? I backed up two movies yesterday(movie only) and each film was 120 minutes. One had a compression of 90% and the other was 77%. I used 5.1 on both, no dts. everything else the same. Am I missing something?

Advice greatly appreciated!!!

[redwudz]

1. Yeah, that's about right. Depends on what you plan to watch it on, though. 70% or lower quality, you will probably notice on a big screen, depending on the quality of the original DVD.

2. Different DVD's are created with different methods. I would assume a high action DVD would need more bitrate, but the machine that encodes it is probably a larger factor.

[Stas]

1. The maximum compression with Shrink is variable. Usually when you go below 55% you can notice the lower quality on TV. every time when you compress below 90% you must perform Deep Analysis!

2. Redwudz is right. The Lenght of the movie is not the only factor. You must have the same bitrate, resolution, fps (PAL or NTSC) etc. And one more thing: The size of the Menu and Extras! If you make a Full Disk Copy they also matter.