Originally posted by ~~~
Any tips for making an identical copy? DVD Shrink seems to say that it will make a copy, but how much is the quality loss?
Well DVD Shrink is transcoding software. You need that kind of softaware to make a dual layer DVD fit on a single layer disc.
There are a few ways to copy a disc:
1. Do a full disc copy with a transcoding program
2. Do a partial disc copy with a transcoding program
3. Do a full disc copy and reencode the video
4. Do a partial disc copy and reencode the video
Option 1 makes an identical copy of your disc, but yields the lowest picture quality. As more data (audio and video) has to be fit on a disc that's actually too small, the "compression" will me much higher, thus lowering the picture quality. If your DVD contains 7Gb of data (or less), a full disc copy can be done with an acceptable image quality.
Option 2 gives you the chance to remove unneeded/wanted features from a disc. As this gives more free space to the remaining items, the quality of them will be higher. The most popular way to do this, is to leave everything but the main movie off. By deleting unwanted audio (especially DTS tracks) you can gain loads of free megabytes as well.
For option 3 and 4 goes the same as for 1 and 2, with only a small difference. The video isn't transcoded anymore, but completely reencoded. This requiers quite some more computational work, but it makes quite a big difference in image quality when squeezing very long movies or so on a single disc. This technique is hardly used though, as it's not that easy to do, it requires expensive software and most people are completely satisfied with the quality you can get from a transcoding tool.
My advice: give DVD Shrink a try!