Can you see any difference once shrunk?

[toyospares]

I have backup up a few DVDs with DVD Decrypter, DVD Shrink and ImgTool.

I understand that DVD Shrink re-encodes the movie to fit onto a single sided DVD-R.

In data compression. shrinking via a different algorithmn doesn't necessarily mean a loss of anything i.e. 7zip compresses 2-10% more than PKZip etc.

When DVD Shrink re-encodes I have seen it claimed that quality is lost.
Is that true?
If it is true then obviously the degree of quality lost will depend on the degree of "shrinkage" required. More shrinkage equals more quality lost.

What exactly is lost?

Does that equate to going from say DVD quality to VHS quality? i.e. how does it relate?

What difference would the average human see?

Does it depend on the type of movie? i.e. dark, light, action, animated etc.

My eyes aren't great and I'm watching on a DVD player connected through a VHS player and via RF to a 20+ year old 34 cm PAL TV. I can't see any difference even on DVD's I've had to shrink to level 10 (about 47% from memory).


Curious minds would like to know.

Thanks.

Toyo

 

[dx]

Does that equate to going from say DVD quality to VHS quality? i.e. how does it relate?

Oh heck no... not that bad! You see DVDs use VBR (variable bit rate) to save on space. If a scene is not all that complex (a beautiful slow moving vista shot) then the VBR can be encoded higher. But if the scene is complex (fast moving car chase), then the VBR has to be lower, else you will see noticeable motion artifacts.

When you re-encode with programs like DVD Shrink, the VBR process will have to be higher to fit it on the 4.7 gig disk. Many DVD 9 movie discs rarely use all 9 gigs (for the movie portion)... the extra features fill this space. Many of them use only 6-7 gigs.

It really depends on the movie. "Terminator 3" fitting on a 4.7 gig DVDR is going to suffer some noticeable quality loss with shrink, but "Legally Blonde 2" will not. In the "T3" case, just split the disk into 2 DVDRs for best quality.

Try to do a few DVDShrink's and compare the quality. In the end you will need to decide if there is a difference or not.

 

[ChickenMan]

I doubt what ever you do will not show up as poor while your still watching on your 34cm TV via RF from your VCR. Even watch the original DVD will be poor quality compared to watching it on a larger, widescreen TV and video directly in.

What ever you do, dont upgrade your TV/VCR as you might be in for a shock when you watch your dvdr's on some newer equipment.

 

[ah64tom]

I notice little to no difference when the "shrinkage" is kept above 70%. I did T3 with DVD Shrink to one DVD-R, and surprisingly enough, on my 34" Sony Vega I could hardly notice much difference. Of course I was looking for quality loss, but the kids dont know the difference and thats the important part.

 

[toyospares]

I notice little to no difference when the "shrinkage" is kept above 70%. .

That's the kind of opinion I was after. Thank's ah64tom.

Was looking a a 46 inch plasma yesterday with set top box receiving the local (Melb, Aus) digital free to air. Very nice. Now all I need it the $7.5k and a bigger house.

We can all dream!!