Well, I know I have certain MP3s that work perfectly fine in WMP and not in mIRC with splay. They work fine with a winamp plugin in mIRC.
I had also thought it worked using WMP, but I wonder if perhaps mIRC doesn't use codecs from WMP, so that it will play any MP3 that doesn't require a special codec, but not ones with special codecs even if WMP has the codec and can play it. Just a thought since I don't know much about how it works.
