Is it worth to do Deep Analysis when choosing NO Compression

[whatisdvd]

Deep analysis on dvd shrink takes additional 45-60 mins comparing just use rip and burn. But if I choose not to compress the video at all, does the deep anlysis still helps to improve the video quality? I've read many posts, it seems that DA only helps when you choose to compress the video at certain ratio. To my experience, DVD X Copy seems to generate better video quality than dvd shrink. When using dvd shrink at no compression rate, the video quality slightly inferior to the origial, such as less bright, sharp and contrast.

Experts in this forum has any experience with this issue? Any reply is highly appreciated.

[Gazorgan]

No Compression = No Analysis

No compression is a straight copy, so Analysis isn't needed. Same thinig for getting the compression down to 100% (dropping audio/subs and trimming begining and ending), no deep analysis needed. I generally don't do deep analysis for anything over 90%.

[Kerry56]

If the video files are small enough that you don't need to compress, then using the "no compression'' option should give you very good results. If you don't think Shrink is doing it well enough, you can try DVDDecrypter in ISO mode for those small videos. Read it in ISO mode and write it to the disk in ISO mode in Decrypter and see if you like it any better.

I personally wouldn't use DVDXCopy for anything, but that's just my prejudice.

[jimmalenko]

...does the deep anlysis still helps to improve the video quality?

Deep analysis doesn't really "improve" the quality as such - You cannot improve the quality of a movie that has no compression. It lowers the bitrate where possible as opposed to compressing the data itself.

What it does is it goes through the movie and works out where it can lower the bitrate unnoticeably throughtout the movie in order to obtain the set compression level. If no compression is specified, then it can keep the maximum bitrate right through and there is no need to attempt to lower it.

[whatisdvd]

Thank you for all the responses, Now I know I don't have to waste hours to back up my videos!

But I still have noticed the video quality is not as good as origial. I use Memorex 4X dvd+r, CopytoDvd to burn, with NECA1300 burner. I don't know wether the lowered video qulaity results from the cheap media I used, or from Dvd shrink program itself.

[adam]

Its strange that you can see a difference even with no compression. If it doesn't compress it then it should be a bit for bit exact copy of the original vobs, minus encryption of course. There's really no way the quality could be compromised, yet you're not the first person who I have seen make this observation. I wonder what, if anything is actually going on.

For a good description of what deep analysis does read DVDShrink's quote in this thread... http://forum.doom9.org/showthread.php?s=&threadid=63587

Essentially deep analysis lets DVDShrink scan the source before compressing to determine the rough percentage of DCT data in each frame. DVDShrink can only compress DCT data, as opposed to motion vector data, so by knowing what it has to work with beforehand, it can compress more evenly.

As others have stated already, if you don't use compression than there is no need for the added analysis. Maybe I'm mistaken but doesn't the latest version of Shrink grey out the deep analysis option if you have no compression set?

[Kerry56]

Get DVDInfoPro and check the id on those Memorex disks you're burning. If they are CMC Magnetics, that may be your problem right there. My 1300a doesn't even like the Ricoh JPNR01 disks I've tried.

[whatisdvd]

Thanks for all the replies! But what is CMC magnetic and where would it be indicated in DVDinfo panel?