How to compress ps1 iso by removing fmv and other media files?

Started by Pariston, May 13, 2022, 10:06:04 AM

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Pariston

I want to shrink games like FF7, Grandia, and Lunar. But I'm not really sure what to remove and how to dummy the media files.

Do I need Poweriso or psx2psp?

MysticLord

For what purpose? If you're not actively playing them then you can un-ecm them which IIRC zeroes out or removes some hard to compress stuff in an ISO, making archives you make of them considerably smaller. I don't know if emulators can play roms with missing error correction, maybe you could ask the Duckstation guy to implement it.

I think they're in here.

https://www.romhacking.net/utilities/1440/

Here's a source code link.

https://github.com/KingDuckZ/ecm

Let me know if you need help using command line programs.

If you are looking for solutions with specific games, maybe you could replace FMVs in specific games with event editing, text, or moving player character sprites/models on a new background or whatever. Events and images take up way less space than FMVs.

Pariston

I'm saving space on my 32gb phone. I just want the game itself and not the enormous fmv media files.

Are you familiar with this program: https://github.com/Lameguy64/mkpsxiso

Apparently this mkpsxiso can dummied out the big files I want to remove. But I have no idea how to compile stuff from github.

2tack

Did you check the releases section on github? It has it pre-compiled already for different OSes https://github.com/Lameguy64/mkpsxiso/releases

Pariston

Yeah finally got it to work, I think. It needs cmd to run.


FAST6191

Classically this would be called ROM ripping (yes it does get confusing) with some of the stuff seen in PC world of... shall we say the shareaza era being the pinnacle of it. In consoles then PSP, original xbox and DS would probably be in a multi way fight for best of.

There are many schools of thought here and approaches you can take.

1) You go into the code and remove the calls for things, or exception handling for when it can't reach them (and FF7's is not good which I can say from very annoying experience).

2) You reduce the size of things. The most primitive version is you get the game (or suitable donor -- when ripping on the DS we would usually use Goldeneye's sound as a replacement for other games), sort by size, copy-paste over everything else and gain a boost that way. More advanced combines most other things here and might see you reduce framerates, bitrates, resolutions and more besides like you would do when ripping a DVD or something. This gets about as annoying as expected as so very few easy video codecs exist, not to mention most people usually want to go the other way and get better quality (the fun and games people were having getting Command and Conquer cutscenes suitable for the modern world being one of the better examples).

3) Relinking. Every new hacker soon runs into pointers. Pointing what was once a small file for 50 files is quite possible with most pointers. Mostly used so people can zero out the other files and boost compression ratios but can also work for a rebuild, albeit not one you are likely to easily do with most ISO handling tools.

4) We start playing outside the lines of things on this site. You will probably first encounter this for games that use CD audio. Play track 3 is just as easy for the emulator to replace with play track3.mp3 that is 10% the size (never mind AAC or anything really fun there), you might also encounter it in older downloads of games that would convert things back to CD audio to burn to save bandwidth in the transfer.
Similar can be done for videos but it is way way way less common.

Final Fantasy 7 is also an interesting case. One of the main nerd facts those around then would learn is the game is actually on all three discs with only the FMV that changes. Do the disc swap trick

tvtoon

The question is not clear enough, but here is the history: people used to rip movies from games, mostly by zeroing the movie data. This works with many games, Final Fantasies had problems because of their massive use and checkups.

If this is the reason, carefully removing XA and videos then compressing the binary images, will get you somewhere. However, if you want to move data on the image things will get problematic in ANY game, as they want that "DUMMY.ZZZ" stuff there.

Pariston

Quote from: tvtoon on May 14, 2022, 12:16:31 PM
The question is not clear enough, but here is the history: people used to rip movies from games, mostly by zeroing the movie data. This works with many games, Final Fantasies had problems because of their massive use and checkups.

If this is the reason, carefully removing XA and videos then compressing the binary images, will get you somewhere. However, if you want to move data on the image things will get problematic in ANY game, as they want that "DUMMY.ZZZ" stuff there.

Yes that. I want a psx rip. I guess zeroing and dummying are the same thing?

May 14, 2022, 04:33:39 PM - (Auto Merged - Double Posts are not allowed before 7 days.)

Quote from: FAST6191 on May 13, 2022, 07:35:35 PM
Classically this would be called ROM ripping (yes it does get confusing) with some of the stuff seen in PC world of... shall we say the shareaza era being the pinnacle of it. In consoles then PSP, original xbox and DS would probably be in a multi way fight for best of.

There are many schools of thought here and approaches you can take.

1) You go into the code and remove the calls for things, or exception handling for when it can't reach them (and FF7's is not good which I can say from very annoying experience).

Final Fantasy 7 is also an interesting case. One of the main nerd facts those around then would learn is the game is actually on all three discs with only the FMV that changes. Do the disc swap trick

Yeah, it seems FF7's fmv is hard to remove because it's tied in to sequence of the next scene.
How about something like Lunar or Chrono Cross? They got enormous fmv media that I would like to remove.