problem with dvd shrink

[Rud]

ive just tried backing up one of my dvds using dvd shrink, i copied the dvd to my hard-drive and then opened the files (compression set to auto as usual) and when i clicked on backup, it said the current dvd size is too big. Seems the auto compression isnt working properly with just this dvd, strange huh?

any ideas?


http://www.rud.nildram.co.uk/sanchez.JPG

[steve2713]

It can't compress it any more, you need to remove an audio track/still frame some of the extras/run it through DVD Shrink twice, etc.

I'd suggest still framing one or more of the extras that you aren't interested in if possible, that would probably be the easiest thing to do.

[Rud]

lol, ive never come across this before, thanx for the advice

[DVD Polizei]

I'd put the movie on one disc and the extras on another.

[HARRYSPADGE]

Hi Rud,

I think I may have the answer to your problem.
I've just done a test by selecting a custom DVD size (in the preferences menu) of 3000MB.
I then hit backup and got the same message as you did.
So my theory is that in your preferences you may have inadvertently selected a custom DVD size which is very low.
To check this select Edit, Preferences and check that your target DVD size is set for DVD-5(4.7GB).
This should sort your problem.

[HARRYSPADGE]

By the way, what is the initial size of the disc you are trying to backup, before compression.

[Sifaga]

i would use vobblanker to removed unwanted stuff before feeding it through dvdshrink

or you could feed it through dvdshrink more than once

[SCDVD]

I have had this happen with DVD Shrink and I have a theory about why it happens. I suspect that when Shrink calculates the necessary compression, it doesn't take into account the audio tracks and extras. If you have more than the typical number of audio tracks, it winds up without enough room for everything to fit. Everytime that I have had this happen, I deselect all of the audio tracks except for the 2 channel AC3 track and it always fits after that.

[DVD Polizei]

SCDVD,

I think you're right. DVD Shrink more than likely only recognizes the first few audio tracks.

[jimmalenko]

In short, DVDShrink works on compressing motion vectors for each frame. Without going right into it (it scares me too much to recall ), ddlooping has explained it here before and there are also explanations on the web as to how exactly DVDShrink's compression algorithm works ...



EDIT:
Found what I was looking for ...
http://forum.doom9.org/showthread.php?&threadid=63587

That covers just about every element of how DVDShrink works and transcoding in general!

The point is that it is not miscalculating the number of audio streams you have or anything like that. Because it does not & cannot process audio, if you have a number of audio streams then obviously this leaves less room to compress the video, so this is why it is this scenario that is generally when you see that DVDShrink can't hit the target size, and why when you deselect audio streams, it then has so much more room to fit the video.

[skebenin]

As a point of clarification, DVDShrink doesn't compress motion vectors. It requantizes the DCT data, which results in more coefficients going to zero, which results in more efficient huffman compression.

Compressed Domain Transcoders (like DVDShrink) do not touch motion vectors. That'd be pretty complicated - you'd have to think in discrete cosine space to figure out how to recompute the motion vectors, rather than the cartesian space we're all used to - a real mind bender.

Hmmm, I wonder if anyone other than a computer science major will find that amusing.

[jimmalenko]

As a point of clarification, DVDShrink doesn't compress motion vectors

You're right - as I said, it scares me to think about the whole process

I remembered reading that link some time ago and the specifics didn't exactly roll off the back of my brain