compression program

Maybe 7z? Who knows, he downloaded them so they could be hacked apart in any way.

Most of those are rips which have no music and fmv's which are taken out.

yea, as Reich said... it could be hacked and few things could have been ripped... so image is much smaller (it could be that tekken 3 ripp that's available on the net...)

ah, okay. I was just hoping to rip all my games and compress them so I don't have to rip them all the time when I want to use them.

its true i have marvel vs capcom 600mb+ uncompressed iso but 50mb compressed(1st 7z then rar)

It sounds like a rip where the music and sounds are taken out.

By taking out the "extra stuff" a PSX program can be small.

so the cd decompresses to 600MB+ to trick the emulator into thinking its a valid disc?

1) CD roms aren't always loaded to capacity. They all have a capactiy of 600~700megs, but may only contain 100megs of data.
2) 7zip supposedly gets very high compression rates, although I've never gotten it to work properly.
3) Things may have been converted to other, more space efficient formats. Any uncompressed audio or video files may have been converted to compressed ones (ie wav->mp3), compressed ones may have been recompressed at a lower quality, exe and dll files may have been compressed with UPX.
4) Some things may have been left out entirely.
5) Any combination of the above.

I ripped Mega Man X4 down to 20mb so I could play it on my pda, and it was 491mb, you'd be suprised at how much of it is music and movies...

Cypherswipe said:

1) CD roms aren't always loaded to capacity. They all have a capactiy of 600~700megs, but may only contain 100megs of data.

Click to expand...

usually when I rip a CD it comes out to the right MB amount. So wouldn't a CD with only 100 megs of data create a 100 meg ISO (some CD's have funky copy protection, so assuming the ripper removes such garbage from the ISO)

_01_ said:

its true i have marvel vs capcom 600mb+ uncompressed iso but 50mb compressed(1st 7z then rar)

Click to expand...

that's probably becouse of data that is on this games cd (try to compress a bmp file, you'll se how small it is after this process )

Yeah, assume they have copyprotection or other data located near the edges of the cd while the gamedata is stored near center: The iso will possibly contain blank sectors (perhaps all 0 bytes or FF bytes) between the copy protection and the actual game data. Those bytes compress well, but they still have to be there to fill out the empty space in the actual iso.

They have to be there unless the iso format is more complicated containing ranges where the data are to be written to the cd (something like the .cue sheets, but possibly even more advanced).