I have an application that enables recording video from multiple iPhones through an iPad. It uses Multipeer Connectivity for all the device communication. When the user presses record on the iPad, it sends a command to each device in parallel and they start capturing video. But since network latency varies, I cannot guarantee that the recording start and stop times are consistent among all the iPhones. I need the frames to be exactly in sync. I tried using the system clock on each device for synchronizing the videos. If all the device system clocks were in sync within 3ms (30 frames per second), then it should be okay. But I tested and the clocks vary quite a bit, multiple seconds. So that won't work. I ultimately solved the problem by having a countdown timer on the iPad. The user puts the iPad in view of each phone with the countdown. Then later I use a python script to cut all the videos when the countdown timer goes to 0. But that's more work for the end user and requires manual work on our end. With a little ML text recognition, this could get better. Some people have suggested using a time server and syncing the clocks that way. I still haven't tried this out, and I'm not sure if it's even possible to run a NTP server on an iPad, and whether the NTP resolution will be below 3ms. I tried out Final Cut Camera and it has solved the synchronization problem. Each frame is in sync. The phones don't start and stop at exactly the same time, and they account for this by adding black frames to the front and/or back of videos to account for differences. I've searched online and other people have the same problem. I'd love to know how Apple was able to solve the synchronization issue when recording video from multiple iPhones from an iPad over what I assume is Multipeer Connectivity.