Need For Speed: Nitro audio format by RolandMunsil at 10:02 PM EST on January 29, 2018
Hello all, idk if anyone cares but I've reverse-engineered the audio format used by Need For Speed: Nitro and posted some info + a decoder here. I describe the whole format in detail here; I don't have a ton of knowledge about formats but it seems to be vaguely like ADX? Anyway, enjoy.
(Also, I realize I probably shouldn't have written it in C# because float math is not consistent across platforms but I'm kind of tired of working on this so a C/C++ rewrite will have to wait)
Afraid to say this is a known format, used by many EA games. The codec is EA-XAS, implemented in FFmpeg or vgmstream (fixed point).
FE_COMMON_STR.abk contains multiple .SNR headers, while FE_COMMON_STR.ast has the .SNS main data. In the .AST, before ~0x680 are the SNR headers/index, then SNS data. Most files should work in vgmstream if extracted from those bigfiles and named .SNR + .SNS. A few like .SPS would work as-is. But some sfx use the fabled "EA-DSP" (not playable ATM), how intriguing.
You can check vgmstream's ea_eaac.c, ea_xas_decoder.c and blocked_ea_sns.c for some info too.
by RolandMunsil at 4:59 PM EST on January 30, 2018
Ah shoot. I kinda figured that might be the case. Ah well, it was fun anyway. Thanks for the info!