Maximum Compression

xariskop · Post by **xariskop** » Wed Apr 29, 2009 12:21 pm

Some can compress files, iso, whatever, better than others.
Egon68 will you tell us your secret?

Post by **hfric** » Wed Apr 29, 2009 12:38 pm

simply
make them prepared with ecm first
then use lhz, arc, uha or 7z (each has its perks)
there you go

but i wouldn't recomend Ecm with Securom or Safedisk protection images,
after the rebuild those clones are not playable

Post by **Virgil** » Wed Apr 29, 2009 1:03 pm

Check this out, dewd. But I really don't see a point to eagerly trying to save 10-20 megs today.

xariskop · Post by **xariskop** » Wed Apr 29, 2009 2:17 pm

10-20mb only?
i recently downloaded the Syberia 1 & 2 The Collector's Edition DVD
from Egon68 and while the i,age file is about 4.35 GB when you open it with ultra iso you see 12G if i remember well.

How is this happening?

Post by **Trey** » Wed Apr 29, 2009 7:28 pm

What the hech is NanoZip? One way to get the size down is to rip the disc image in bin/cue format, offen you can compress the .bin file with ecm by about 100mb. It depends on the original discs structure, but 100mb from 700 or 800mb is like 15% or something isn't it, that's pretty good. I've seen stuff compressed way, way down with uha and kgb, but that's slow and prone to errors.

Post by **hfric** » Wed Apr 29, 2009 8:44 pm

so lets test it :
Braid org size= 145 734 690

RAR best = 107 190 257 bytes
7z Ultra 4 gig = 108 973 905 bytes
Nanozip ultra 4 gig= 102 035 406 bytes

decompress time on AMD 6000+ x2
Nanozip = 1m 52s
7zip = 19s
RAR = 10s

compress time
Nanozip = 3m 12s
7zip = 1m 2s
RAR = 1m 3s

edit: and just for kick's Uha
compress time
Uha ULTRA so much i am crazy= 4m 21s
Uha decompress = 1m 24s
Uha size pack = 105 313 407

Post by **Virgil** » Thu Apr 30, 2009 12:48 am

xariskop wrote:10-20mb only?
i recently downloaded the Syberia 1 & 2 The Collector's Edition DVD
from Egon68 and while the i,age file is about 4.35 GB when you open it with ultra iso you see 12G if i remember well.
How is this happening?

I doubt it, unless there are some empty junk protection files on that DVD. 10-20 megs is what you're going to save from 1 CD by using various compression tools with different settings, including ECM. Really, when I had slow connection I tried to squeeze as much as possible from each archive, but now I just see that this is pointless. You will spend more time extracting stuff from the archive, when downloading it. Stick with WinRAR and forget about everything else.

Post by **hfric** » Thu Apr 30, 2009 1:14 am

in other words padding data to bump the data to outer layers for max reading speed

Post by **Egon68** » Thu Apr 30, 2009 12:21 pm

Here's one example:

bin+cue uncompressed = 587 Mb
bin+cue+ecm uncompressed = 512 Mb
bin+cue compressed with WinRAR best = 337 Mb
bin+cue+ecm compressed with WinRAR best = 260 Mb

Disc contains only data.

Post by **hfric** » Thu Apr 30, 2009 9:00 pm

compress it with 7z and you get it 20 mb smaller, but 7z is crap for images with cd-audio

Post by **Shattered** » Tue Jun 02, 2009 5:59 pm

If you really want the maximum compression possible at any cost, you should check out PAQ, especially the paq8px range:

Code: Select all

http://encode.ru/forum/showthread.php?t=342

Various models for exe, audio, image and other datatypes are embedded in the program. The latest version also incorporates an ECM model for CD-images.

Too bad it's too slow for practical purposes.

Jaz · Post by **Jaz** » Mon Jun 22, 2009 1:42 pm

but i wouldn't recomend Ecm with Securom or Safedisk protection images, after the rebuild those clones are not playable

Hello, hfric?

Are you sure about that? I had the impression that ECM does not touch the data it cannot recompute.

If that's true I will stop using it right away. (for the record I have tested 200+ images to make sure they unecm back to the original, But these probably didnt have those protections.)

Post by **hfric** » Mon Jun 22, 2009 5:57 pm

yeah, it borks the image for those protections and also borks TAGES and STARFORCE CPD

well Ecm the things he writes about protection is BS http://www.neillcorlett.com/ecm/how.html

i will say this
Safedisk looks for its own DATA (it makes 3 or 4 files) so you will think Ecm will don't do harm to your image BUT also for the bad Sectors its like 1024 or more in the begging or in the middle of the cd

Securom looks for DPM of each file thats in ... well somewhere in EDC/ECC codes

TAGES ... well it hides the protection data in line out/in(some say it overburns the CPD, and most readers have problems with reading overburned data ) and most programs don't read it , thats why Vcd or MDf image from Tages are 860-900mb per one cd or 4,8-4,9 gig per DVD
--------------------------
when ECM removes EDC/ECC codes... in securom it borks the damaged sectors that are the protection...in securom it borks the dpm... tages lulz it deletes the CPD data

So why was it made, ECM was only made for only ONE THING to STORE CONSOLE GAMES MORE EFFICIENTLY NOT PC GAMES...
Ecm is used for Sega CD, PSONE, AMIGA CD32 ,Sega Dreamcast,Sega Saturn,Atari Jaguar CD ,Philips CD-i ,Neo-Geo CD,TurboGrafx-CD

only exception to this rule are old DOS games in ISO, Bin/Cue format

BUT... still Ecm corrupts your Bin/cue data if the image has CD-Audio (crystal clear becomes crackly messy crapy chaos of bumps)... thats why most console rips/re-dump projects extract the audio in FLac or in Monkey and then the data is processed with ecm and 7zip or Nano-zip

Jaz · Post by **Jaz** » Tue Jun 23, 2009 1:08 am

Mmmh OK. This is kinda weird and I have not seen any evidence of messed up audio and such things. It should not matter if it's a PC or console game either. I'll look into that source code I guess.

freakboy · Post by **freakboy** » Tue Jun 23, 2009 11:53 am

I would not recommend compressing isos, because there are users who do not know how to use all these fancy programs. They have daemon tools installed and speak only their native non English language. Even loosing tens of megabytes is not worth it.