I'm switching HDMI video from SONY A7s and GoPro with a Blackmagic Design ATEM switcher, and mixing in Powerpoint slides. I'm converting the Camera HDMI with Blackmagic Up/Down/Cross convertors so that they play nice with the Powerpoint Laptops. The audio is the output of the Mackie audio mixer, with multiple microphones. I notice a little latency on the projection screens. What do you use to get everything to sync? I also plan on sending audio and video to Blackmagic Web Presenter, but haven't used it yet. Any suggestions to make my life easier?