Hacking How to decode PS Vita RIFF audio files?

[OkazakiTheOtaku]

I'm trying to decode a PS Vita audio file that appears to be in RIFF format. The source of the file is one of Persona 4: Dancing All Night's DLCs.
The file was packed into a standard .awb, which I used AWB_unpacker.exe to extract. The problem is, AWB_unpacker just assigns it a generic .bin extension. Looking at the file in a hex editor suggests that it is a RIFF WAV file.

None of the standard tools in my toolbox (Foobar 2000 w/VGMstream, VGMToolbox, WinAMP, VLC, Audacity) know what the heck to do with the thing.
If I give it a .wav extension, then Foobar can detect how long the song is, but complains about a missing ACM codec.

I can't find anything out about this file online and can't seem to find any convertors. Does anyone know how I can decode these?

EDIT: Here's some more information I was able to extrapolate, if it can help.

 

[Ryccardo]

I would try to convert it from ATRAC9, just as a gut feeling... Failing that, that "BG6M" could be a clue but nothing a plain web search knows about...

Nothing else jumps flagrantly to the eye, and ACM is just the old windows framework for audio compression (if you've seen the format/quality selector of XP or earlier sound recorder, you've seen ACM codecs)

 

[OkazakiTheOtaku]

I would try to convert it from ATRAC9, just as a gut feeling... Failing that, that "BG6M" could be a clue but nothing a plain web search knows about...

Nothing else jumps flagrantly to the eye, and ACM is just the old windows framework for audio compression (if you've seen the format/quality selector of XP or earlier sound recorder, you've seen ACM codecs)

Thanks for the reply. How would I go about trying to convert from that specific format?

 

[Ryccardo]

How would I go about trying to convert from that specific format?

at9tool - though I don't remember if it only converts TO atrac9 or both ways, haven't really ever used it

 

[OkazakiTheOtaku]

at9tool - though I don't remember if it only converts TO atrac9 or both ways, haven't really ever used it

Alright, cool. Thank you. I'll try that.