About 20 years ago there was a similar problem with demoscene creations. It was hard to capture demos in realtime in all their glory. So one guy created a tool[1] that waited for a frame render and presented proper time to demo so that frames would be paced properly. "All popular ways of getting time into the program are wrapped aswell - timeGetTime, QueryPerformanceCounter, you name it. This is necessary so .kkapture can make the program think it runs at a fixed framerate (whatever you specified)."
Dont forget .gif webcam streams! Just keep sending new frames!
It's rather off-topic, but the linked blog is by the guy who made .kkrieger, the tiny first-person shooter (only 96kB) in the early 2000s. Though the website for it is now gone, as .theprodukkt doesn't exist anymore, apparently. Nice to see his other stuff, didn't think to look at the time.