Well, it's likely the same image formats and metadata values that are found in GTX files (because those are the image formats that the hardware is optimized for), but AFAIK it's in a completely custom format.
I dug into my old notes on this format and made a wiki page for it with all the info I have on it. I'd really appreciate if you guys could add whatever you come up with to the wiki page so it'll stay documented somewhere anyone can easily find it! Having to scour the Internet for little hints about formats that other people have already figured out but didn't document properly is the most annoying thing ever so I like to try to keep things organized. Here it is: http://www.metroid2002.com/retromodding/...al_Freeze)
On META, keep in mind that it's originally a data blob from the pak. The pak has one giant META section which contains the meta info for every file in the pak that has it. The unpacker locates the data for the resource it's unpacking and creates a new META section at the end of the file to place the data into. That's why the META data is split off into a separate part of the page from the normal TXTR format description, and why the META header isn't described on the page (but if you need to know how it's formatted it's the same section header format you can find everywhere in basically any Tropical Freeze format).
I dug into my old notes on this format and made a wiki page for it with all the info I have on it. I'd really appreciate if you guys could add whatever you come up with to the wiki page so it'll stay documented somewhere anyone can easily find it! Having to scour the Internet for little hints about formats that other people have already figured out but didn't document properly is the most annoying thing ever so I like to try to keep things organized. Here it is: http://www.metroid2002.com/retromodding/...al_Freeze)
On META, keep in mind that it's originally a data blob from the pak. The pak has one giant META section which contains the meta info for every file in the pak that has it. The unpacker locates the data for the resource it's unpacking and creates a new META section at the end of the file to place the data into. That's why the META data is split off into a separate part of the page from the normal TXTR format description, and why the META header isn't described on the page (but if you need to know how it's formatted it's the same section header format you can find everywhere in basically any Tropical Freeze format).