1
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 ...
Only top voted, non community-wiki answers of a minimum length are eligible
Related Tags
video × 466raspbian × 78
hdmi × 55
streaming-video × 51
camera × 41
python × 27
audio × 26
omxplayer × 26
ffmpeg × 26
pi-3 × 23
display × 22
raspicam × 22
webcam × 22
vlc × 17
hardware × 16
composite-video × 15
streaming × 14
pi-2 × 13
boot × 13
opencv × 13
kodi × 13
media × 13
pi-3b+ × 12
output × 11
pi-zero × 10