Go to Boss' website and download the owner's manual for you machine and you can have this information at your fingertips for future reference. It's pretty straightforward in its description.

Quote from the manual:
Waveform data must be 8- or 16-bit WAV or AIFF format. In
addition, only a sampling rate of 44.1 kHz can be used. No
data in any other format can be copied.
* Compressed WAV files or AIFF files cannot be loaded.
* Extremely short waveform data (less than approximately 500
ms) cannot be loaded.

When using the BR-1180CD, you can copy (import) SMFs
(Standard MIDI Files) on CD-R/RW discs as user rhythm
patterns.
Copying SMFs created on a computer to CD-R/RW discs lets
you easily increase the number of user rhythm patterns.
* Use of the BR-1180 requires installation of the optional CDIBR-
1 CD-R/RW drive.
1. Using your computer, write the SMF you want to
import to a CD-R/RW disc.
* The prescribed format for CD-R/RW discs is “ISO9660 Level
2 Mode 1.” Note that you may be unable to import using other
formats.
* You can import SMFs (Standard MIDI File) with a maximum
file size of 240 KB. SMFs exceeding this limit cannot be
imported.

End Quote.

Best of luck.