ROM Hack How would I edit files found in games?

[YugamiSekai]

I extracted the files from Kid Icarus: Uprising and there was only one file format that I was familiar which was .arc (because of brawl modding), but I noticed some file formats that are unfamiliar to me (.zrc, .bcstm, .bctex, .moflex,). How would I edit these files? And could I use BrawlBox for the .arc files?

 

[A_Random_Guy]

AFAIK, moflex is a video format. bcstm is a 3DS music format

 

[YugamiSekai]

AFAIK, moflex is a video format. bcstm is a 3DS music format

How do I edit those formats?

 

[A_Random_Guy]

Moflex is currently uneditable. bcstm is idk. Wait until some much more talented so answer your question

 

[ketal]

Moflex can't be edited because no one has implemented the codec necessary to encode that format. You can still watch them.
BCSTM is the audio format that's used also in WiiU. There are plenty of converters.
zrc. are probably (D)ARC archives. You might need to RE it because it could be a custom format (capcom does this, for example)
bctex is some type of texture, never heard of an extractor for that before

 

[FAST6191]

File extensions are not set in stone or enforced -- .arc is probably some form of archive/compressed file bundle but it might not be the the .arc format you might have seen else. Granted this is a Nintendo game so I would not be surprised if it was. Do check with existing tools (or open it in a hex editor and check against the known .arc formats) but don't be surprised if it is different/new.
moflex is a video format seen on the 3ds. I think there is a half decent decoder ( http://gbatemp.net/threads/released-moflex-player.400053/ ) but encoders are a bit thin on the ground (and I am not sure there is even anything in the leaked SDKs). You could edit some stuff manually, possible trim some frames and if you only want to subtitle something then there are ways around that (rather than edit the video you overlay an image).
bcstm is indeed a sound format https://gbatemp.net/threads/release-brstm-bcstm-conversion-tool-beta.378702/
bctex is a 3d texture format if memory serves, not sure what goes for decoders right now though http://gbatemp.net/threads/release-every-file-explorer.373615/ would be your best bet for a starting point.

Anyway the better answer to "How would I edit these files?" is probably going to have to be learn to hack and reverse engineer things -- the 3ds is still relatively new to this ROM hacking lark so if you want to get far in it you are going to have to forgo tools and get your hands dirty pulling things apart. Fortunately it is similar enough to the DS and wii that you can learn from those.