You disabled the huffman? Why not recompress and optimize the table?

4MB. The limit for a standard SNES game.

What about a 24-bit bitpacking MTE algorithm? I don't know exactly how good it is, but Metal Slader Glory uses that and it's got a pretty big script.

Typically, in this exact situation SNES games I've seen will utilize some LZ on top of the dictionary. That will probably do the trick for you depending on how large you can make your buffer. Adding the huffman back in in addition to dictionary would also most likely do it.

I really wouldn't advise going over 32meg because it becomes a fictitious cartridge unless you match one of the custom mappers used by a few of the other real games. You have to remember it's more than just mirroring. It's a cart mapping. The 'standard' cart mappings don't go above 32megs, so unless you use one of the others, your cart mapping doesn't exist and emulators won't play it. You may be wondering why I keep throwing the word 'cart mapping' around when we're talking ROMs and emulation. Well, the SNES can't see anything by itself. It's just a dumb bus. So, you NEED some sort of address mapper supported by things even for a made up ROM that would never have a real physical cart.

Personally, I think adding LZ will get the job done. I've seen it done in several SNES games with good results.

P.S. Probably 75% of those who own copiers own them 32meg or less. So, you're of course ruling out that audience which may or may not matter to you.

For what it's worth, the game plays fine in bsnes. I don't know if that's a sign that it's using the correct 'cart mapping' or not.

Won't work. The SNES DQ games use huffman for a reason. The script pointer table holds a pointer to a block of 8 or 16 (depending on the game) pointers, and the pointer holds the bit index as well. The game decompresses exactly that many text boxes (1 - 8/16) to get the decompressed text.

See the problem? LZ is a streaming compression, the current byte relies upon the decompression of the previous bytes. DQ does not decompress the entire script into RAM, so it has to use a compression algorithm that you can jump into at any point to decode.

The reason you see LZSS in so many SNES games is because they mostly use scripting systems and such that have blocks for each "area", "scenario" or "chapter." It's much easier to stick those small blocks into the top of the 128kb SNES WRAM. A 300kb game script wouldn't fit so easily.

Personally, I think DaMarsMan is underestimating the compression power of combined huffman and dictionary. 70% shouldn't be too hard with that, but sadly I don't have the time to help.


No, not at all. SNES emulators use hacked up mappers designed to get optimal compatibility, because the people dumping carts don't agree upon the importance of also recording the cartridge PCBs to get correct mapping. It'd take them five minutes a cart, but they won't do it, simply because we're really good at bullshitting things now.

And I can't afford to purchase 5,000 carts to do it myself :(

So I should compress with DTE+MTE first and the compress again with huffman.