b3c8632006
not something to concatenate Q10, and it starts by withdrawing the question's own premise. BGM_001 is not three sub-waves of 10 KB / 4.47 MB / 4.67 MB: the 10 KB is the bank header. A bank is exactly TWO waves, and across all 32 BGM banks on the disc the two always have the SAME duration -- equal to 0.01 s over lengths from 37 s to 277 s. That alone kills intro+loop and kills two halves of one piece, both of which require unequal lengths. Four banks appear to break the rule and do not: BGM_106-109 are the known leading-region straddle, and the giveaway is that the entry named BGM_107.slb contains BANK id=1108. The seek packet counts pin each join exactly, so they realign to the same two-equal-waves shape rather than being dropped as noise. That trap goes in METHOD. Then the roles, by decoding both waves to PCM. They are sample-synchronous: transient-envelope correlation searched over +/-5 s peaks at lag +0.00 s, and both waves stop at the same millisecond, 167.663 s. Two stems of one performance, meant to sound at once. Wave 1 is quieter, has almost no bass and is far more L/R-decorrelated, which reads as a surround-rear pair or a second intensity layer -- I cannot separate those two from the file, and say so: ChannelMask is 0x0002 on both, and this game's channel metadata is already documented as meaningless. Two things the port needs that are NOT on the disc, both marked as authored: the track is not a seamless loop (BGM_001 fades out and is followed by 6.15 s of silence, no loop-point field found), and nothing names which bank the menu plays -- all 32 BGM cues are numeric.