Small question about psp isos

[terron]

Ok so I use PSP ISO compressor 1.4.
Now why is it that some isos get compressed more than others?
These are the sizes of the files:
:confused:

Bleach Heat the Soul 5
Uncompressed:565,920 kb
Compressed:445,736 kb 78% original size

DBZ: Another Road
Uncompressed:475,584 kb
Compressed:323,040 kb 67% original size

Def Jam FFNY
Uncompressed: 1,539,936 kb
Compressed:512,207 kb 33% original size

Naruto: Phantom Fortress
Uncompressed:619,392 kb
Compressed:545,187 kb 88% original size

Sonic Rivals 2
Uncompressed:387,330 kb
Compressed:260,827 kb 67% original size
--------------------------------------...
Why do they vary so much?
I used the same settings on all.
Thank you very much.:confused:

[Triv1um]

Maybe you should buy the UMD and then you dont need to worry about sizes. Yes?

Still, games have dummy files and files that are bloated and easier to shrink. I think.

I'm not sure but i think that is the reason. But get UMD's, they are faster ;)

[Eviltaco64]

Maybe you should buy the UMD and then you dont need to worry about sizes. Yes?

Still, games have dummy files and files that are bloated and easier to shrink. I think.

I'm not sure but i think that is the reason. But get UMD's, they are faster ;)

What are you talking about? Loading from UMDs is a hell of a lot slower.

[Triv1um]

What are you talking about? Loading from UMDs is a hell of a lot slower.

Play VCS in ISO.

[terron]

Thanks for the answer, could you explain the point of bloating games?

[bah]

terron: I could be wrong, but:

The data is read from the inside of the disc outwards.

The game's data does not take up the full capacity of the UMD, so the it is written to the inner part of the disc and the outside part has no information.

The outside of the UMD disc is (sightly) larger than the inside, meaning in one rotation there is more information as the track is 'longer'.

The fact that there is more information in one rotation and the disc is spinning at the same speed means data can be loaded faster from the outside of the disc.

If they put dummy files to pad out the inside part of the disc, they can push the game data to the outside and get slightly better read speeds meaning quicker load times.



Some types of data compress better than others. If the game had .wav audio then it would compress a lot.
If the game uses an already compressed file type like .at3, mp3 or whatever PSP games use then that data is already compressed and there is not much a lossless compression method can do to shrink them further.

Dummy files can either be identified and removed, or are often 'junk' data with a lot of similarity between all the info, this means it can be compressed a lot very easily.

Game companies should put random data in the padding files, that would mean ppl would at least have to strip them out manually, they could probably put checks on some parts of the padding files to stop the game running if they are gone as well also.

[wiggy fuzz]

nintendo ds carts do this as well, i've no idea why, though.

[bah]

wiggy fuzz: DS games have dummy files or just that they can be compressed?

I have NFI why a cart based game would have a dummy file.
To fill up the memory chip the cart is on and slightly lower the number of games you can fit on a flash cart?
*Shrug*

[Eviltaco64]

Play VCS in ISO.

Well, I've played Vice City Stories as a UMD before and it took like 1 minute - 2 minutes to load.

[mike_jmg]

In my experience the games that can be compressed more are the ones that have less videos on them

[bah]

mike_jmg: Videos encoded with modern video/audio codecs are already highly compressed (take advantage of similarity), so files encoded in them do not compress much further.


Zip a .wav file and look at how much it compresses it, then zip an .mp3.

[mike_jmg]

ehm

you're kind of proving my point
that if it has a lot of videos it cannot be compressed much further