compression level wuts the quality diff?

[lukasz70]

hi,
using dvdshrink, just wondering how big the difference is in the compressions in terms of quality,

at this point i have to use level 5 which is 25% will that give me a very noticable difference in quality?
what would be acceptable

ps. its for a series, brother bought the dvd's, just making backup for myself, so its 3 episodes per cd, kinda wanna keep it together

thx

[redwudz]

Well, very generally, below about 70% you will see some quality loses compared to the original. Below 50%-40% a lot of loses. Below that, use a different method or more discs. Just my opinion.

[jimmalenko]

Levels ?

Weren't they left in DVDShrink 2.3 ?

I suggest updating to the latest (& greatest, & final) DVDShrink, V3.2. It contains many enhancements.

[guns1inger]

Regardless of levels or % as a measurement, there is no definative answer to your question. Factors that influence the outcome include how much you are compressing by, whether or not you use deep analysis and AEC, which AEC setting you choose, as well as how much the original was compressed in the first place, and how well it was encoded. Some disks will accept trancoding down to 80% of their original size and stll be quite acceptable, while others will show definite signs of problems when transcoded down to 90%.

For my money, 100-90% Shrink with deep analysis and AEC is a neat, fast option. If I have to shrink it further than that, then I go over to DVD Rebuilder and Procoder (OK, LS, you've convinced me) to get a decent result.

[manono]

OK, LS, you've convinced me

Oh no, a CCE defector to blurry DVDs.

I thought your first paragraph was quite good. I might add that it also depends on what you'll be viewing the result. A CRT television will be much more "forgiving" of transcodes than will an HDTV or computer monitor. I see posts around here to the effect of, "I compressed 7 GB of vobs by 50% using Shrink and it looks great". It depends so much on the "overhead" allowed for further shrinkage that no definitive answer can be given. And in fact, in general, the larger the original total vob size, the more leeway you'll have for shrinking it. That is, again, in general, this overhead is measured by the original average quant, and the lower it is initially, the more compression you can get away with. That plays to your point about it depending on how much it was compressed originally. So redwudz' 70% might be fine for one DVD, and as you mentioned, even 90% might be too much for another DVD.