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Manually recompressing 7zip ROM

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ner0:
Hi.

I apologize in advance for the topic because it is somewhat out of scope.
I am wondering if on occasion it is possible to just manually extract a ROM in zip format and re-compress it in 7zip format.
At the moment I know that the answer is: yes and no

I should give a specific example: I have a "Street Fighter II - The World Warrior (910522 World)" zipped ROM, and I want to extract it and compress it back with 7zip LZMA2 instead. Even though I did try several times with and without the exact same arguments that clrmamepro uses for 7z (a -y -r -ms=off -mx9 %1 %2), the resulting ROM archive never works with the emulator - bytesize comes very close, but that's about it.

Comparing both clrmamepro and manual 7z produced archive, one thing in particular stands out: the files archived with clrmamepro have various levels of LZMA2 compression while the one produced manually applies the same ratio to every single file within it. I can see that clrmamepro is issuing multiple compression commands (per file?) instead of a single one for all files, but since I don't understand fully how the process works I am still left with the question: having the same source rom files, is it possible to achieve the same resulting "working 7z archive" without using clrmamepro?

Obviously that if I want to process a full set or even a big number of ROMS I should not be doing manual work, but I still wonder if this can be achieved in individual instances or not; and if not, why?

Thanks in advance.

oxyandy:
Probably out of scope for Roman to answer..
Not fully sure of what you are doing or what is going on with your emulator... but
Take a zipped archive drop it onto t7z.exe it will make a 7zip archive, does that resulting archive work with your emulator ?
If so, you could then drop a whole folder of zipped (or incompatible 7z) archives onto the EXE and it will convert them all
https://sourceforge.net/projects/t7z/

ner0:
Well, that was... easy.
I wasn't aware of such tool and how it parses the files apparently differently than using plain 7z; it does work perfectly with maximum compression with said ROM, I'm assuming it will work with others. Thanks a lot, I've been going in circles for hours!

ner0:

--- Quote from: Lewis-H on 07 November 2020, 09:55 ---https://www.hostinger.com/tutorials/how-to-use-7zip-to-compress-files

--- End quote ---
Thanks, but that wasn't at all what I asked about.

Sjackson3289:
A very creative and great idea, I think this idea will be implemented and invented many other ideas.

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