So I’m currently working on a project where I’m connecting two studios and another location all in different countries via my system in the UK.

It’s a virtual environment project with both studios on green screen sets with 2 cameras each.

Each camera feed (2 from Location 1 & 2 from Location 2) is being sent to me as an SRT feed, which I’m brining into SRTminiserver and then taking NDI feed of that into vMix and separate ISO records.

The third location is a pinned Zoom call. Location 1 & 2 are also sending a single camera feed to this call for them each to pin for eyeline, with Loc 3 pinning both.

Location 1 is sending it’s SRT feeds via Wirecast and an Epiphan Pearl
Location 2 is sending both from a vMix system

Location 2 has reasonable sync between it’s two feeds

Location 1 has several seconds between it’s two, as a fix I’ve got them to add 2000ms latency on feed 1, I’ve then added another 37frames of delay in my vMix along with about 1800ms of audio delay because of the way they’re routing the audio their end.

Where it starts to become an issue is where there is a three way conversation taking place, Location 1 asks a question, 2 & 3 respond reasonably quickly, but there’s a good few seconds delay on Location 1 as he catches back up to the conversation.

For the most part it’s been manageable, especially as this is a pre-recorded project and can be tightened up in the edit, but a) clearly this wouldn’t be great for a live and b) the delay I’ve added in vMix doesn’t affect the ISO records which are straight off the NDI from SRTminiserver.

The reason for SRT in this case is to get better quality than WebRTC for the studio feeds to be able to start an offline edit to then conform to the camera rushes when we get them.

So, clearly at the moment I’m pushing my currently level of understanding with SRT, so any pointers to any best practices, guides, information, anecdotes etc for managing the latency between locations to enable a smoother conversation and how to sync feeds without timecode would be very much appreciated.

Thank you in advance!

Matt