I own a projector which is obviously on the opposite site of the room than the audio system. I'd like to keep everything cableless, so one RPI is connected to the audio system, the other one to the projector. What would be the best posibble solutions in keeping both RPIs in sync when playing back a video? Thanks in advance!
Make the RPi connected to the audio system essentially a bluetooth speaker. Stream the audio from the RPi that's playing back the video. Most video player apps have sound delay/advance configurable. - once the audio delay/advance is set for a particular video it should hold audio sync throughout playback pretty well. From tutorial at Raspberrypi.org forum here https://www.raspberrypi.org/forums/viewtopic.php?t=235519 (check for up to date instructions). Install Pulseaudio and bluetooth module. Set user permissions configure A2DP sink restart bluetooth start pulseaudio Set up device trust (with the video RPi) and you should now be able to use it as an audio receiver.