INT 66 - IBMSND driver - REPORT AUDIO DRIVER CAPABILITIES
        AX = 068Ch
Return: AX = capabilities (see below)
        DX = playback rate if fixed-frequency playback
SeeAlso: AX=0689h,AX=068Dh

Bitfields for capabilities:
 bit 0  can play audio in background
 bit 1  data is massaged
 bit 2  driver plays at fixed frequency, resampling input data to fit
 bit 3  driver uses timer interrupt

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