Hello guys,

I have a question regarding VMIX SRT Output.

First of all, I use "long distance" SRT input feeds day-by-day with a very good result. The latency is always sub-second, between EU and USA, Asia, etc, and the link is real stable - of course you have to setup the link with the correct parameters.

Yesterday I tried to send back a PGM feed and sound to a remote locations. I'm tested this with Larix Player and Haivision Player Pro. The latency was always higher than 1 second - and this was a local network. I played with the output settings, H.264, HEVC, hardware and software encoding, low-profile encoder, etc., without any success. The latency was always more than 1 second. I can't figure out why its occur... is there any tips, idea, how can I eliminate this? With VMIX CALL (webRTC) the latency is less than 10 frame...

Thank you!

Yes, you are right, the transmission latency is fixed with the SRT protocol. But here I'm talk about the "glass-to-glass" latency.

The SRT transmission from my iPhone/iPad to the VMIX systems is fine, the glass-to-glass latency is sub-second, so I have a really good results.

The other direction is more problematic: SRT transmission from VMIX output to your iPhone or iPad. I don't know why, but the "glass-to-glass" latency is more than 1 second. Probably this is happen because of the VMIX processing and encoding time, or something similar, I don't know. So I would like to find a way, how can I decrease this processing time as little as possible.

I will try to test out some NDI to SRT util, it can be a workaround, but hey, this is not a real solution. The real solution if we can lower the latency with VMIX SRT output. On input side - it works really well. On output side, its working, but with a relative high glass-to-glass latency, and one-on-one interview situation this is too high, and its not acceptable by the clients.

And its not an SRT latency or player side latency/buffer problem, its quite clear.

VMIX Call can be a good alternative for the return feed, but its a closed thing, so you can't implement in your own solution. And using two device for the conection is not a comfortable option.

Here is a test setup as an example.
Top left is SRT loopback, top right is NDI loopback.

SRT end to end latency is 266ms or 8 frames.

srt-latency.jpg (296kb) downloaded 9 time(s).

Hi Peter,

did you hear anything back?
I'm having a delay of around 3 - 5 seconds and would like to know how to know how to reduce it as much as possible.
Using vmix -> SRT NimbleStreamer -> SLDP player
Even playing the stream locally with the SLDP player, I get over 2 second delay.

cheers
lee