Best way to see compression artifacts.

[From a Buick 8]

Currently I am backing up using MTR (full disc), then DETOX (Version 1.x), and then toast 6 to burn. I have been very successful (over 200 + and counting and very few problems).

I will usually use DETOX to do a movie only disk (so I have the least amount of compression) and then if there are extra's I would like to backup I will do a full disc so I have those. So for most movies I end up with 2 DVD's.

Ok enough history... I am working on the movie Carlito's way the movie clocks in at 145 minutes (just the movie alone is over 7 gigs), so I thought I would split the movie across two disc, thinking that if I compress the whole movie to one disc it would look bad.

Well I did both, I compressed the whole movie to one disc and I also split the movie across two disc, and I am having trouble seeing any loss of quality between the two methods.

Maybe this film is not the best one to use for this type of test, but what should I look for to try and pinpoint any quality loss. Or is there a better film out there that would do a better job and highlighting these type of issues.

Sorry for the long post and I know this is an odd question.

[jtoolman2000]

Well, that just shows you how good some of the compression methods actually are. I bet if you play both discs on a good DLP or plasma 50+ inch TV, with HDMI imputs, you will see some diference. Even then, it might be minimal. It all depends on the original source and how that was created, meaning, how much it was compressed to begin with. Movie length being equal, some movies will back up ( Copmpress ) better than others. You can never really tell what th out put will be like. It is all depending on the Bitrate that was used on them from original raw source to DVD.

[From a Buick 8]

Is there a specific movie you can think of that would be a good "worst case" for me to experiment with?

Thanks for the quick reply.

[Case]

You could DTOX a really long movie like LOTR, or compress a regular duration movie to a smaller size, say 2.5 or 3 GB.

[DeadLily]

I tried to join the 2 disks of the 6-hour Jesus of Nazareth onto one disk. It joined, but couldn't do it in the 4.4G of space. So I fed the results back into DTOX to try again, and while it made it smaller, it was still too big. So I kept re-compressing it until I finally got something that was small enough to burn. But the results had lost so much resolution that it was like watching it through a screen door.

(Meanwhile, I've been able to fit 7 episodes of Buffy onto a single disk, and they're still very watchable.)

[thoughton]

I've found Pitch Black to be one of the worst normal-length films to compress. Otherwise any 3+ hours film will also look pretty dodgy in the action scenes.

3 hour Deep Space 9 discs are also a bugger, because of all the smooth gradient spacestation backgrounds.

Any film with lots of explosions as well. Ocean scenery is also notorious. And soccer games also look awful when compressed.

[From a Buick 8]

So if I find a space based underwater soccer movie that is over 3 hours long that should do the trick .....

Thanks for all the help, I know it is a odd problem, but I have been very happy with all of the films I have compressed and I was just wondering if I was not seeing something. Maybe I need a bigger TV (I use a 32" Sony).

I will take episode 3 and keep compressing smaller and smaller until I see a difference.

[jtoolman2000]

You may never notice anything on 27" TV. I have a top notch 52" DLP HD TV and depending on the movie, compression and post processing done in DVDSHrink. I may, or not notice anything. It is simply based on The quality of the original. I have seen horrible, grainy original movies that look awful on my big set but good on my 27". Compress this even slghitly and it will look horrible.