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Here's what a section of the non game data in an xbox iso looks lik



Maybe we can use jpg sort of compression on xbox iso's

I tried converting a 7mb chunk of non game data, by first adding a bmp header from a real 7mb bmp image.

Intrestingly if you open-->save as-->tiff, psd, raw, or pxr-->then open-->tiff, psd, raw, or pxr-->then save over the original bmp.

There is practically no difference only 1 par2 block, which if we set the par2 block size very small this could be as little as a few bytes.

The only problem is when saved to a tiff, psd, raw, or pxr the size is the same as the bmp.

Does anyone know if theirs a file format like tiff, psd, raw, or pxr, that would save and be smaller than the original bmp, but when it is saved back as the original bmp, gives us back are bmp, with maybe a small sized repair.

.....

ahhhh

Random data is random data, no matter which format you save it as. It simply can't be (losslessly) compressed in any way.

r09 wrote:Random data is random data, no matter which format you save it as. It simply can't be (losslessly) compressed in any way.

It can be losslessly compressed. But theres no advantage because it doesn't get smaller.

What you mean is if you save it from a 32-bit.bmp to a 16-bit (making it smaller) then from 16-bit back to 32-bit, you loose all the original data. Or at least that what I was trying to say.

You could try png. It compresses lossless. Here's more info about its compression scheme: http://en.wikipedia.org/wiki/Portable_N … ompression
Considering that this is random data and not an actual picture, I doubt you'll see any significant compression gains over another file type. Wouldn't hurt to try though. 

its kinda sad png hasnt been mentioned until the 6th post! but anyway, is it feasible?

I know of a way that could compress this sort of image. I couldn't make the program, and I'm not a 100% it would work, but it might.

An xbox iso is 7433027584 bytes

If if it was slpit into 7433027584 seperate files. 1 byte per file.

And every byte was numbered from 0000000001-7433027584 and kept in order

If a program was made to scan the iso.

When it see's the first byte (which just say it was) FF, it could then create a folder called FF, then all the FF bytes would be grouped into this folder but numbered by the byte position in the iso.

So say the first byte was FF and the 0000010099 th byte was also FF. tHE FF folder would contain the bytes @ 0000000001 and also 0000010099 and so on and so forth.

Once the iso had been split into sepertate bytes and seperate byte folders.

Then all the seperate folders could be compressed individually.

Then to get the iso back all the files would be extracted to a single folder and joined in number order, to form the iso again.

The amount of disk space needed to store the byte positions' numbers would be even bigger than the actual uncompressed file Let alone the fact that Windows would pad these 1-byte files to 4096 bytes (?) anyway (edit: Granted, not if you compressed the files afterwards ^^). If this worked, even the biggest files could be compressed to a few KB, which is physically impossible. Forget it, random stuff like that is nearly uncompressible.

Any one know of any actuall programs that can split a 100mb or above into seperate 1 byte files numerically ordered, so far I've only found tools that can split up to 999 files. I need something that can split to 1 byte files, and able to at least handle 100mb files (1073741824 bytes)

I'm beginning to think we have no chance other than winrar store compression. But it was worth a go.