Embodiments herein describe automatically synchronizing the output of source devices connected to a system reference point through an IP network in a media production studio so that the outputs are aligned when they reach the system reference point. In one embodiment, the system reference point device exchanges a plurality of messages and timestamps with a source device. The source device uses the messages and timestamps to determine a transmission delay between the source device and the system reference point device. The source device uses the transmission delay to determine a video transmission correction factor, which the source device applies to modify the time at which it outputs a signal so that the signal is aligned with signals output by other source devices when the signal arrives at the system reference point device through the IP network.