GZIP compression safe?

[nate2000]

Hi,

So I read through thread about GZIP and wanted to know is it safe to go ahead and compress all my games or are there any bugs or problems that might occur in doing so.

[refraction]

It's pretty safe, however newer versions of the emulator support CSO compression, which is pretty much as good and much cooler

[nate2000]

Okay cool so should I use CSO instead?

[Blyss Sarania]

CSO compresses faster. Gzip compresses slightly better.

Take your pick. See this comparison I made:



But gzip takes about 5 times as long to compress.

[nate2000]

Thanks for graph, is that with CSO compressing at highest settings also? plus which application are you using for CSO compression please.

[Blyss Sarania]

You have to use maxcso for making CSO for PCSX2 as it is the only CSO compressor that can handle files larger than 4GB properly.

https://github.com/unknownbrackets/maxcso

The coder of maxcso is also the guy who added support for it to PCSX2.

Those graph were with default settings which are basically the highest. It's command line and you can't tweak the compression settings too much unless you wanna get super advanced, in which you can pick the algorithm. But the default is the strongest.

And for the gzip ones I used 7zip on gzip setting if you wondered. CSO files compressed in about 10 mins each with maxcso, gzip files took about an hour each.

[nate2000]

Brilliant thanks for detailed response, I'm going with CSO.

[sirdaniel]

My test on MOH Frontline US
ISO: 3,15GB
CSO: 2,73GB
ISZ: 2,62GB

Wonder which one of compressed formats above has faster decompression or random access.

Can this cso tool be used for psp discs too?

[Blyss Sarania]

Can this cso tool be used for psp discs too?

Should be. CSO is a standard format. The only reason you have to use maxcso only for PCSX2 is some PS2 ISO are > 4 GB. This was never originally accounted for in the CSO format since it was designed for PSP UMDs which could not exceed that size. But maxcso was originally written for PSP CSO so it's fine. Only later was > 4GB support added(at the same time unknownbrackets added CSO support to PCSX2)

Also CSO supports random access natively. Gzip doesn't we get around this by having PCSX2 generate an index file the first time it loads a gzip compressed ISO which allows us to do a form of random access(block random access). Neither introduced significant overhead in my tests. Unless your PC is already struggling with PCSX2 it shouldn't be a problem.

[Ryudo]

I don't remember this, but CSO for PSP causes quite a bit longer load times in some games. Is that the case for PCSX2 as well?