Does DVD-RB 'process' files even at 0% compression like DVDShrink does...

Vurbal

It's possible that the pixel count is approximately the same but what's in each pixel may not be. Did you compare the result pixel by pixel? Sometimes the eyes can see what can't be easily measured through bean counting. If the sharpness is altered are pixels being dropped?

 

Knowing that the chrominance and luminance is of the same pixel count and even color balance doesn't mean that they are of the exact same values. Isn't it possible that a minor shift in any of them can provide the same overall count but a different result? Isn't that essentially how one adjusts the picture quality on their TV sets?

Hmm! Didn't we have a similar debate on this about a year ago?

 

Vurbal

So you're saying that the actual degree of luminance and chrominance are being measured or just the pixel location? Does it include variances in brightness and color tone? Remember that a minor shift in brightness (luminance) or a slight pull toward the blue or read spectrums can occur within the same pixel but it would still be in the same location wouldn't it?

 

I just noticed that you had finally released your test results. Thanks for taking this matter to the end vurbal. As I said, I'm not a pro in DVD copying, but what you say makes sense. I can only back that up with a qualitative analysis - I used Shrink to edit a DVD in an uncompressed format and then processed though CCE SP 4 passes. I couldn't notice any difference between the original and the copy (Sony Trinitron 61 or so inches.) I think that if someone disagrees with the your conlusions, they should publish their own test results that clearly show that Shrink reduces the quality, otherwise discussions don't help much without any empirical data. If you go deep enough, you can successfully argue that the copy is not identical to the original. Bu then again, you can use the same argument to argue that no two original DVD's are exactly the same since their surfaces don't all have the exact same 3D contours burned in by the photons in the laser of the burners in the factory. Does this mean that this is relevant? No. It can't be perceptible by humans and can be left out. Believe me, in physics they make much rougher approximation when they build a spaceship or the equipment for your DVD burner. If we go any deeper, we'll have to decide whether God decides to hide the extra kb to return the energy to the universe as entropy. Forget it.

 

I've done some studying of SSIM and it doesn't do exact comparisons it only does similarities. But that being said I agree with Lumbastio in that the majoriy of claims made by others regading Shrink are qualitative measures. Therefore I've down loaded SSIM and I'm going to step back and for a while and do my own tests.

 

vurbal

Give me a break. LOL

I started writing avi script a year ago and then I got sidetracked doing other things. Now I'm back to studying it again so I might be sending some question your way.

From what I've read the value 1 denotes the similarity.

I may prove myself wrong but I still believe that DVD Shrink somehow filters even a ripped no compression result. From what I've read SSIM does a pretty good job of making comparisons.

Question does it also compare bitrates?

 

Vurbal

For that, we can all be thankful. Without questions there would be nothing to learn.

I have a 4 day weekend coming up, I might be able to give it go.

 

vurbal

Thanks! I will.

 

Good luck Sophocles. Let's hope that our suspicions will finally be put to rest by confirming in this thread that the uncopressed format of Shrink does not alter the edited DVD quality. Remember, that if you find infinitesimally small differences between the original DVD and the one processed by Shrink, there will still be the issue whether that small difference in numbers can also be distinguished visually. So if your meter stick is DVD Remake, in that case you might have to analyze the same DVD processed by Remake to be able to compare it to Shrink becase in case of a very small difference it might turn out that all programs affect the DVD in the same manner. Here is a suggestion: for very subtle differences, small errors are going to have huge effects on the results. So it would be best if you compare the processed copy not to the DVD directly, but to the exact same file ripped onto your hard drive. This way you will eliminate the small differences that your burning hardware creates evertime it copies a DVD. Again, if the differences are going to be large, this won't matter, but it won't hurt.

 

Lumbastio


It's already known that DVD Shrink under no compression renders a small difference in physical size. You can verify that by ripping a DVD with Decrypter and then running that same ripped file through Shrink targeted to another folder and then compare the two. I've also had compressed DVDs that weren't compliant but could be made so just by running it through DVD Shrink. So there are already small differences between the original and the no compressed output but the question is does it affect picture quallity in some way.

 

Sorry for bumping this super old thread, but has there been a final conclusion to the debate about Shrink altering files.