If it helps as a fallback solution....
I'm also on Yosemite 10.10.1 with Kodi b5 and I am having no problems at all, but I'm not using HDMI nor S/PDIF for Audio output.
My config is Audio Output device - Default, Built-in Output....with 2.0 speakers connecter to the headphone socket on my 2011 iMac.
Adjust display refresh rate to match video - OFF
Sync Playback to display - Enabled....
Mac OS X - Audio sync off with refresh rate switching (nightly builds)
Joined: Feb 2012
Location: Perth, Oz
2014-11-29 17:56 Post: #76
FAQ: Chromebox vs Amazon Fire TV
Setup - FLIRC, Logitech Harmony Remote and XBMC