Aladdin in Nasira's Revenge (PC) - .ASF by Nicknine at 8:56 PM EDT on June 2, 2018
The game stores music in ASF files which appear to have unknown encoding although they do have a header. I assume the audio is 22050 Hz mono like in PS1 version. There's also a codec module called asfcodec.adl in the executable directory if it's any help.
Found this old thread. kode54 commented that it seems like modified Microsoft ADPCM. Must be a custom codec made by Argonaut Games. Some guy posted a decoder but without the source code.
I tried before but assembly is not my thing. I saw a bunch of functions doing (seemingly) ADPCM nibble decoding, but I wasn't familiar with the algorithm (some stuff looked vaguely inpired by PS-ADPCM?).
If somebody properly describes it I could implement.
Hmmm, somehow can't find the option. I'm using "IDA Pro Free" (7.0?). I'll see if I can procure something better, or could you post the pseudo-code? (decoding functions are the 4 long-ish subroutines just before the entry point/DLL main, I think).