Simultaneous, synchronized stream from multiple location over LTE

Hi Guys! :slight_smile:

I’ve received an inquiry today from one of my returning customers for a live stream featuring 4 different groups of people (pandemic regulations allows maximum 25 people in my country) performing the same dance in different locations simultaneously, scattered in different place of the city - outdoors. I’ve done some streams like that in the past incorporating remote streams from drones to my RTMPminiserver and then converting it to NDI for easy Wirecast mixing. However, it was not perfectly fluent due to the internet connection of each guy streaming to me - it had some freezes, frame drops and the latency was in fact increasing all the time. Is there any solution you could recommend for performing such gig? I can live with some frame drops but would like to be able to maintain the same relative timeline of each clips, so that If I sync them prior to the performance they won’t go out of sync in a moment. Thanks for any advice in the matter! :slight_smile:

SRT possibly, you can set fixed buffer size on both ends

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Definitely sounds like a fun challenge! If you can find something that will have a consistent delay, you could measure that delay at the start and then offset everyone’s local playback by the right amount so that you end up with a video feed that’s already in sync by the time it hits your mixer, that way it doesn’t matter at all what the actual delay is for the stream and you don’t need to find a solution with the lowest delay. What you do need to look for in that case is something that has a consistent delay that isn’t going to skip around. SRT is probably a good place to start experimenting!

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@aaronpk @gimzo

Thank you for the suggestion guys, I’ve already started experimenting with SRT before I read your messafe. I did some house test over wifi using SRTminiserver to convert it to NDI to use the streams it in wirecast. As you mentioned Aron, the delay isn’t an issue, the issue is the drift over time - the increase / decrease of the delay on each source. Initial tests in the “perfect enviroment”, by which I mean all four cameras on the same fast WIFI and then NDI over cable into wirecast works like a charm - I’ve noticed no drift after 10 minutes. Now I will do some fields tests and see what happens when streaming to the SRTminiserver over LTE - would there actually be a drift. On the other hand, I’ve found some encoders and dedicated software for a perfectly synced streams via global timecode (like Adobe Media Server), yet they are waaay beyond the budget for this project not to mention how complex they are to run.