Are films compressed on commercial DVD's

[JohnWB]

When I use DVD Decryprer & DVD Shrink to copy just the main movie from a DVD I usualy have to compress the movie. I was wondering if the movie is compressed on the origional DVD and if so how much compression is normaly used.
Also, what is the max compression that can be used when copying without causing any degredation of the movie when viewed on the TV

[lumis]

mpeg2 is a form of compression.. its not like they have a 20gb mpeg2 file and ran it through dvdshrink to bring it down to dvd9 size..

and as for your second question, thats kind of unanswerable.. what looks acceptable to you, might look like crap to someone else.

[JohnWB]

Ok I will as a different way. Is there a way to find out what the origional compression is

[jimmalenko]

originally (waaaaay back in the beginning) it is uncompressed

If the DVD uses VBR, then every frame has a different bitrate - open your DVD in PowerDVD and turn "information display" (or whatever it's called) on and you'll see the bitrate fluctuate greatly. BitrateViewer might also assist.

If you have a Dual Layer burner, you can do a complete 1:1 copy of your DVDs with no extra compression required on your part.

[pfh]

Also, what is the max compression that can be used when copying without causing any degredation of the movie when viewed on the TV

My experiments have shown that once you start going over the 70% mark you start to notice loss with Dvd Shrink.

On some, I'll adjust the "extras" on a dvd to 50% and maybe use stills for the menus thus giving more size to the main movie to reach the 70% mark. This sometimes allows the whole dvd to be backed up.

[jtoolman2000]

By virtue of the fact that DVD uses MPG2 as the video source already means it was compressed. As was also explained, the original movie is almost always encoded by various means to allow it to either just fill the DL disk along with simple manus ( Minimal Compression ) or like most, about 2/3 or even 1/2 of the disk so they can included all sorts of extra crap ( Higher and often detrimental compression ) It was in the begining of DVDs that E the consumers demanded more BANG for the buck when it came to DVDs. After all they did cost more than VHS. So it was partly our fault.

It has little to do with the LENGTH of the original either. I've had a 2 hour movie that required a lot of compression to do a movie only / single audio backup. I've had other movies of the same length that would fit without any compression.

If I take these two ORIGINAL DVDs and view them. Each containing a 2 hour length movie. The first example, the movie looks and sounds GREAT. But no extras,,,, darn. Movie utilized almost the whole disk. Second movie already looks as is it was compressed about 60% in shrink But I have losts of extras I will not even watch.

When I back up the 1st, I compress in shrink, subsequently briging down the quality. When I backup the 2nd one I do not have to compress at all but the original's highly compressed quality was already BAD to being with.
Granted there are some filters and setting that will allow you to preserve as much of the original quality. These may ir may not help

Results of this experiment??? They both end up about the same viewing quality when backed up to DVD/5

The 1st actually looks a bit better due to its original VBR encoding. The 2nd one was not encoded with VBR