To anyone interested in overlaying text with Videosync, while we don’t have native solution yet, I did make a prototype with Max/Jitter a while ago. The device outputs its texture to Spout/Syphon by default, so the only thing required to get it into Videosync is using an External In device:
Since this is a Max/Jitter approach, this won’t work when using Videosync in Networked Mode.