GSF files are, essentially, a GBA ROM that has had all unnecessary (to audio playback) data removed. What I'm trying to say is, you can't extract GSFs from a ROM. When ripped, they'll loop endlessly, with no effort on your part (aside from the effort already put forth to rip the GSFs in the first place). As for fading (and for that matter, song lengths), that's often done by ear. That is, when listening to the GSF, you decide at which point the file has looped twice, and use that time as the song end (it's part of the tags in the file. It's *not* part of the originally ripped GSF). The fade is simply added to that (often in the amount of 7-10 seconds).
As for the ripping process, you should be confused. It's not easy, and a "step by step" guide is unrealistic for a multitude of reasons (largely because every game is different, so the process needs to be catered to the game being ripped).
As unknownfile said though, you can try to use saptapper to rip GSFs. I've never used it, so I'm not sure what's involved in that. However, if I understand correctly, you'd need to find the offset (the hexadecimal address in the ROM) of either the song data (the sequences), or the program data (the driver), I'm not sure which, and put that into saptapper. So long as the game in question uses Nintendo's sound driver (many games do), saptapper should be able to rip it for you.
If the game does not use Nintendo's driver, then the process is much more involved, requiring that you know some ARM 7 (I think) assembly langauge stuff. Since you have to ask the question ("how to rip?") in the first place, I feel safe in saying that being able to rip a GSF set (without saptapper) is way beyond your skill level (read up on assembly langauge first, that's at least a step in the right direction). Even with saptapper, I'm not sure the process is very user friendly.
Sorry to sound discouraging, but what you're asking is something that can't be answered easily. Chances are good that it'd be easier for someone else to rip the game in question (which isn't likely to happen, I think), than it would be for them to answer your question in a way that you'd be able to use to rip your own GSF sets. I've never done a rip myself either (well, I did a 2SF set, but that doesn't count. The tools to rip 2SFs are literally point+click=done), and I've been here for years, if it makes you feel any better. Mouser X over and out.
there's a possibility the set you want has already been ripped though, since knurek is insane(ly awesome) and saptapped a whole load which aren't available on GSF central - http://2sf.hcs64.com/gsf/ - i believe they all have loops and fades too.
by unknownfile at 9:25 AM EST on February 16, 2009
if you really are serious though, go read gbatek and all the fun stuff relating to audio registers
Unkownfile isn't known for making friends, and Knurek is on his bad list. I'm sure that he won't forward your request (or he might in an unfriendly way, just to be a nuisance). More importantly though, is that the games you've requested are, I'm pretty sure, not using the Nintendo driver, so they can't be ripped with saptapper. In other words, to be ripped, you'd have to do it the difficult, confusing, manual way (which requires knowing assembly).
I could be wrong, but I could have sworn that Knurek already ripped all the GBA games that were compatible with saptapper. If they're not ripped, then I really doubt they can be, with saptapper. Mouser X over and out.
by unknownfile at 5:42 PM EST on February 16, 2009