Can uncompressed copy degrade?

[vidkid123]

I've copied DVD's using DVD Shrink and DVD Decrypter/IFOEdit/Nero. In one thread I participated in, someone pointed out that the video quality should be the same as the original if you are not compressing it further. When using Level 0 on DVD Shrink and using DVD Decrypter straight to Nero, I swear I see a slight degradation in picture quality (although it still looks pretty good). Aren't we copying digital files to digital files so it should look the same right? Or is something lost in the decryption process?

[hakko504]

Why not demux a the video and use some sort of filecompare function to see if it has changed? Or the AviSynth compare I mentioned in this thread¨. (http://forum.doom9.org/showthread.php?s=&threadid=48346&highlight=avisynth+compare)