SRT Minimum Latency (Server Side)

[Chris P]

In my testing, I am restreaming SRT to the Ant Server over a LAN where latency is not an issue using the srt-live-transmit tool. The reason for doing this is my hardware encoder does not support the streamid feature so when I restream SRT I am adding the streamid.

e.g.  srt://server:5200?mode=listener -> srt://server:4200?mode=caller&latency=20&streamid=WebRTCAppEE/test

When I add latency=20ms this parameter does not take effect until latency is greater than around 120ms. I'm assuming this is because the minimum/default latency on the Ant Server is 120ms?

If this is correct, is there a way to override this? Restreaming is over a LAN with negligible RTT/packet loss so I do not need 120ms 

 

 

[Mohit]

18 hours ago, Chris P said:

In my testing, I am restreaming SRT to the Ant Server over a LAN where latency is not an issue using the srt-live-transmit tool. The reason for doing this is my hardware encoder does not support the streamid feature so when I restream SRT I am adding the streamid.

e.g.  srt://server:5200?mode=listener -> srt://server:4200?mode=caller&latency=20&streamid=WebRTCAppEE/test

When I add latency=20ms this parameter does not take effect until latency is greater than around 120ms. I'm assuming this is because the minimum/default latency on the Ant Server is 120ms?

If this is correct, is there a way to override this? Restreaming is over a LAN with negligible RTT/packet loss so I do not need 120ms 

 

 

Hi @Chris P,

How are you?

I think that 120ms is a characteristic latency of SRT and it is an expected behavior.

Please let me know if I misunderstood.

Thank you 

[Chris P]

Hi Mohit,

Yes, you are correct. My question is if there is a way to negotiate lower than 120ms with the Ant Server? In my testing, I change the SRT latency in to the Ant Server and measure the delay in the webrtc video I am viewing. It seems that if I lower the latency below 120ms there is no effect. 

SRT Latency /  WebRTC Delay

        20 ms   / 430 ms

        120 ms / 430 ms

       150 ms / 460 ms

Thanks,

Chris

[Mohit]

1 hour ago, Chris P said:

Hi Mohit,

Yes, you are correct. My question is if there is a way to negotiate lower than 120ms with the Ant Server? In my testing, I change the SRT latency in to the Ant Server and measure the delay in the webrtc video I am viewing. It seems that if I lower the latency below 120ms there is no effect. 

SRT Latency /  WebRTC Delay

        20 ms   / 430 ms

        120 ms / 430 ms

       150 ms / 460 ms

Thanks,

Chris

Hi @Chris P,

There are no such configurations parameter specifically on the server side as it is expected.

You can fine tune the latency with -tune zerolatency 

Let me know if it helps.

Thank you

[Chris P]

Hi Mohit,

Understood. Thank you for your help.