use SRT in vMix, you should have a latency under 1 second.

see wowza SRT description here
wowza cloud srt

AFAIK keyframe interval has no impact on streaming latency

Regarding network buffering as explained in the manual
Network Buffer
This is the maximum number of seconds vMix can keep buffered at any time and reflects the maximum streaming latency
from vMix. (Note that streaming servers and players add their own buffers on to this time)
Increase the Network Buffer if the maximum network speed available is unreliable.

Again this should not impact latency if your upload speed is adequate.

The only parameter I'm aware of is the FFMPEG rtbufsize parameter that is required to smoothen the stream flow from vMix (uncompressed stream) to FFMPEG.
However this is expressed in MB (like 128 MB or 256 MB) and not in seconds so it's difficult to say whether it relates to the difference you're noticing. But it obviously has a slight impact on delivery time. You can try reducing this value by writing your own FFMPEG script to encode and push your stream to Wowza. (Use EXT out and vMix DSHOW virtual device in FFMPEG).

Apart from that, imho, the extra latency could be the result of the signal quality you're sending to Wowza. Most hardware encoders (you did not mention which one you're using) have pretty low encoding parameters like "profile", "level" for H.264. Those determine the nature, the complexity of the signal to decode on the wowza side as well as the time it takes to re-encode to HLS (I suppose that's what you want, again you did not mention it). For example, "Baseline" goes faster than "High", 3.1 goes faster than 4.2. You can make tests with these parameters to check whether you see any difference.

Another reason I can think of is Covid related : more streams at the moment. It means more power required on the platforms side and most of them have reduce their casual settings for best performance in favor to more delivery power. Transcoding is highly CPU intensive.

My 2 cts...

Great feedback, thank you. We have been using the Epiphan Pearl as our encoder. Wowza specifies setting the KFI to 2 to get the best latency results. Changing it does increase latency. I didn't try lowering the profile, i will do that next.

this is rtmp push. here is the wowza doc we follow. when they refer to segment size, in the epiphan pearl that is the KF setting. Is this different in vmix?
https://www.wowza.com/do...th-wowza-streaming-cloud

Thanks again for all of the guidance. I have set up SRT in Wowza but i am a bit confused, if someone could clarify that i am on the right track:

1. In Wowza Cloud there is a choice for vMix, but this seems to be just for rtmp. Also it seems to me that the set-up in the 'Streaming' set up in vMix is also just for rtmp.

2. In Wowza Cloud I would set it up as 'Other SRT'. But this only gives you a url with our account embedded, and a Port number. Then I go to the SRT screen for Output 1 and check the SRT box. But it asks for a 'Pass Phrase' that Wowza does not supply. If I leave it blank I get an error indicating the need for Authentication.

If I am able to get past that then I am a little unclear what turns on the SRT stream. I think i would go to Outputs, SRT and then Enable 1. Is this the correct procedure? Am I missing something?

Why even bother respond if all you can contribute is RTFM or go ask someone else.
I stumbled across this thread while also trying to setup an SRT stream to Wowza. It is not at all intuitive that SRT streams are configured on the external output settings rather than the usual streaming output. Does it matter if you're already using the external outputs for an SDI card? Also, for some reason, vmix refuses to connect over the url wowza provides srt://xxxxx.entrypoint.cloud.wowza.com. I have to use the public IP address but even then the latency is no better than rtmp.