IC8: DVD backup half the size at 99% setting... ??

[Murdock0815]

Hi all

I just re installed Instant Copy 8 to test out the latest update for it. I took one of my "The Simpsons" and let IC8 back it up.

First of all, I changed some settings in the registry manually since the hidden settings editor places them in a different place (the usual recommended settings).

The DVD is about 7.8 Gigs in size.
I let IC run a complete backup to aim at a new DVD size of approximately 4.35 Gigs. The final output was 3.88 Gigs.

I ran a second backup, now aiming at a final size of 5.1 Gigs- approximately aiming at the difference of my setting and the resulting output of the first backup.
The output was 3.99 Gigs.

Now comes the interesting bit.
I ran a third backup, telling IC to leave all titles at 99%- with IC telling me, the outcome would be around 7.5 Gigs.
The resulting output was 3.99 Gigs (again).

Now, whats this about?
Is this because the Simpsons is a really easy to compress cartoon show that already is at a maximum at 3.99 Gigs? Or is this a bug?

Heh I love my IC8...

[Murdock0815]

Well, judging from the numer of replies, no one really has a clue as to what causes this.

BUT, I might just have a stupid, but working conclusion for this!

Remember I said to do a full back up of a 7.5 DVD and it came out as 3.9 GB? No matter what I told IC of how big the output should be (I enabled the always ok button), it wouldnt come out bigger than 3.9 GB.

Then I tried something else.
I told IC to aim for a DVD9 BUT reduced all titles again so it should result in a ~4.35GB output.
Interesting enough, it came out as 6.35 GB (???).

Then I had vision ;)
I remembered from the first test, that with a DVD5 setting, my output was 3.9GB instead of 4.35.
So I took this difference (4,35/3,9=~1,11) and edited the IC8 registry "DVD5DestSize" to this setting:
Default 4454
New Setting from me 4940 (4454*1,11=~4940)

Then I let IC8 do its "magic" again.
You wouldnt believe it= it gave me a nice 4,36GB output. Even if this exact number might just be luck for now, it gives us a whole new idea of how IC works or doesnt it?

With this method, you still have to go through encoding at least twice (to check the output difference), but at least it works...

[MackemX]

undersizing has been mentioned a few times and here is my very old explanation HERE (http://www.deano.dsl.pipex.com/backup/sizing.htm) :)

I guess most people gave up on IC due to this random sizing that took a little mastering

I created a few methods on getting better filesizes with IC HERE (http://www.deano.dsl.pipex.com/backup/ics.htm) but they may be outdated now. Although it's for version 7, it's probably similar in version 8 :)

[Murdock0815]

Im well aware of the undersizing problems with IC- but its new to me (with IC8) that changing the size of the final media (ie DVD5DestSize) gives out better results rather than aiming at the desired size in the Title/Compression window.

Know what Im getting at?
How come, that 2 full backups

a) aiming at ~5GBs in the compression settings, using the "always enable ok" button
b) aiming at ~5GBs, set in the registry

give out completely different results?