Compression percentages... how is it possible?

[ironmanDD]

Hey, I'm trying to backup 2 different movies with Clonedvd2 and I'm a little confused about compression..

Both movies are exactly 2 hours in length (give or take a few mins), I chose to keep only the menus, main movie and AC3 5.1 AUDIO on both backups..

So on paper, the two backups are damn near identical... menus are similar in size, main movie and audio are all relatively close in size...

however one backup gives a 68% compression and the other 85%... how is it possible to be so different in percentages when they are almost identical on paper...

For the record, both play back with excellent quality but why the difference in compression?

[jagabo]

Look at the videos in this post:

https://forum.videohelp.com/threads/295672-A-problem-for-video-experts?p=1811057&viewfu...=1#post1811057

They are compressed with Xvid but the issue is the same. Some video is more easily compressed than others. The bitrate used in your two movies is different. So to fit them on a single layer DVD one has to be shrunk more than the other.

[ironmanDD]

can the bitrate be adjusted or is it automatic? if i were to forget clonedvd2 and encode with cce can i adjust the bitrate?

[Moontrash]

1 title could have more frames than the other

1 could have a different bitrate etc

basically...what jagabo said

[fritzi93]

one backup gives a 68% compression and the other 85%... how is it possible to be so different in percentages when they are almost identical on paper... ?

If your assumptions are correct, there shouldn't be such a wide difference.

Maybe CloneDVD2 made a calculation error? Seriously, it's not unheard of.

Are the output folders closely similar in size? If so, don't worry about it. And welcome to the forum.

[EDIT] You guys got in before me. If the resolution, runtime and destination size are approx. the same, then surely the bitrates must be close to the same? I'm just not seeing it.

[Moontrash]

i've had 2 hr titles that were waaaay over encoded to be 7.6 gb's in size....from that down to a 5 is a major compression rate

i've had 2 hr titles that were 5gb's...barely any compression needed

[fritzi93]

i've had 2 hr titles that were waaaay over encoded to be 7.6 gb's in size....from that down to a 5 is a major compression rate

i've had 2 hr titles that were 5gb's...barely any compression needed

Okay, dunno what I was thinking of. (None of the tools I've been using for a couple years now give compression values.) Yes of course the originals may have different sizes (and bitrates) to begin with, irrespective of runtime. Thanks.

[jagabo]

I thought CloneDVD was like DVD Shrink. What's it's telling you is the movie on one of the source DVDs is about 6.32 GB, the other about 5.05 GB. So the first has to be compressed to 68 percent of it's original size to fit on a 4.3 GB DVD, the other to 85 percent of it's original size.

[ironmanDD]

What's it's telling you is the movie on one of the source DVDs is about 6.32 GB, the other about 5.05 GB. So the first has to be compressed to 68 percent of it's original size to fit on a 4.3 GB DVD, the other to 85 percent of it's original size.

I checked the size of the source dvds and yes you are exactly right. So the difference comes down to the original bitrate on both movies correct?

If thats so, is it possible to change bitrates? How do scene releases manage to release long movies and always keep high bitrates?

[manono]

if i were to forget clonedvd2 and encode with cce can i adjust the bitrate?

Of course. In fact you have no choice but to set a bitrate. And if you know anything about what you're doing the results will be better than anything coming out of DVD Shrink or CloneDVD2.

So the difference comes down to the original bitrate on both movies correct?

Yes.

If thats so, is it possible to change bitrates?

Yes, of course. But not with DVD Shrink or CloneDVD2, although changing the percentage also changes the bitrate. You can't just set a bitrate, only a precentage.

How do scene releases manage to release long movies and always keep high bitrates?

They use whatever bitrate they can, given what else they're keeping from on the DVD (menus, audio, extras, etc.), relative to the length of the movie. That is, if the bitrate is high, then maybe they removed the extras. And often the releaser doesn't give the correct bitrate in the NFO for one reason or another (usually incompetence).

[ironmanDD]

Ok great... for longer movies I've been using rebuilder and cce, but cant figure out how to change the bitrate... i have rebuilder pro instaled with cce 2.50.. how do you adjust bitrates? I dont see this option anywhere

[manono]

Oh, I thought you meant the manual use of CCE. DVD-Rebuilder figures the bitrate for you so that you wind up with a (pretty) full DVDR when done. If 4.32GB isn't enough and you want to boost the size by another 100MB or so, you adjust the Target Sectors in the INI file.