.xdelta format instead of .ppf

[Xifanie]

I'm making this topic because, well, ppf sucks.

If you want to give it a try: http://www.romhacking.net/utilities/704/

Pros:

• Great compression*
  
• Much faster patch creation (about 2-3 faster than PPF-Studio WITH compression)


• GUI can associate to .xdelta files for quickly applying patches


• Copies surrounding data to save file size, and avoid "raw patching" copyrighted data (as it stands, PPFs from shishi extended images are illegal)


• Makes the image match the filesize of the original one used for creating the patch if it's too short

*JotF patch: .xdelta 4mb raw / 3.4mb 7zipped ... .ppf 20.4mb raw / 5.9mb 7zipped

Cons:

• Cannot be patched on unclean ISOs


• The GUI is not official, and thus Windows only


• Linux version of xdelta might be buggy

If we use .xdelta alongside FFTOrgASM .xml files, I don't see the necessity of using PPF anymore. Of course, I can't force anyone... but I always hated that we'd provide patches contained copyrighted data like that.

[formerdeathcorps]

Why can't it be patched on "unclean" ISOs?  Is this a checksum issue?
Also, how would copying surrounding data save filesize?  Wouldn't that only make the patch larger?
Lastly, since game-patching is technically illegal anyways (in any form), why would the distinction between "raw patching" and "patching from base" matter?

I agree that PPF is not a good system, but unless this has soft-patching abilities on ePSXe or pSXfin, I don't see it being decisively better.

[Xifanie]

It's not a checksum issue.

For example, if I make a patch restructured by shishi, (just making all this up) the patch will say to copy the knight spritesheet from 0xC65000 to 0xCC9000. So yes, using a couple bytes to hold the information to copy huge blocks of data from a location to another saves a great amount of filesize. And it's for this reason you can't patch more than once; it will copy data that is now altered, so it screw up everything. I can't even make the game load past the PlayStation logo with an image pasted twice.

The problem with providing raw data is FFH itself. It puts this website at risk. Yep, I already know everyone using FFT images and even patching them is illegal, but that's more of a problem on an individual (person) level.

pSXfin doesn't support soft patching, I don't know about epsxe. Even if epsxe does, it's a shitty emulator that not everyone uses.