While REX files can be loaded into Digital Performer's nanosampler instrument, it's not intended to be a REX player, as it does not support triggering of individual slices or time-stretching independent of pitch.

To use REX files in nanosampler, first import the REX file into DP. If the REX file provides one soundbite that is the length of the entire file, drag that into nanosampler; otherwise, merge the slices into one soundbite, then drag it into nanosampler.

Alternatively, you can drag REX files onto an audio track in DP to rearrange, stretch, or compress the slices.