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+--- Thread: Should latency numbers add up to total latency? (/showthread.php?tid=1257)
Should latency numbers add up to total latency? - davidb - 06-27-2020
The attached picture shows the diagnostics for someone I was playing with. The audio interface latency is 6.0 ms (mine was the same) and the internet latency is 14.5 ms. These add to 20.5 ms and yet the total latency is showing as 51 ms. The numbers were fairly steady. Even if you add in the jitter (should you?) the sum only comes to 27 ms. Would you expect the sum of individual latencies to add up to the total? In other sessions with different people I find they usually do.
Subjectively we could detect no effect of any latency on our ability to keep together. It felt just like playing in the same room. In a session with someone in Rhode Island (I am near London) we had a total latency of 80 ms of which 60 was internet. It was impossible to keep together with that amount of latency. One of us had to lead and the other to try to keep with that. Not very satisfactory. If 80 ms is almost unplayable it seems unlikely that 51 ms should be perfect. I am therefore wondering if the reported 51 ms is wrong and that it was actually nearer the 20 ms sum of interface and internet latencies.
On a separate point I notice that Frame Size is 10 ms and red. What causes that and can I change anything? We each have the Frame parameter set to 5 ms. Is that the same thing?
RE: Should latency numbers add up to total latency? - Hans Peter Augustesen - 06-27-2020
Perfect total latency is 0 ms
But 0 is of course impossible.
10 is almost perfect. No average people can hear/notice latency below 10 milliseconds.
20 is good.
More here:
LATENCY, mostly TOTAL LATENCY
> https://forum.jamkazam.com/showthread.php?tid=171
The person you are playing with is using WDM driver.
Not good - or not as good as ASIO driver.
WDM is by JamKazam called inferior - and JamKazam recommends not to use it. It has usually higher latency and so, lower sound quality and is more unstable
Audio Interface:
Latency = 6
Input Jitter = 0.47
Output Jitter = 0.52
Frame Size = 10
Internet:
Latency = 14.5
Jitter Queue = 12.3
Jitter = 6.2
Total Latency = 51
These are the numbers.
Then we must add your audio interface 6 ms. Plus your audio interface Input Jitter and Output Jitter. And Frame Size. I assume, hm!
Complicated matter - I can not figure it out, exactly
Internet Jitter Queue 12.3 and Jitter 6.2 suggests a poor internet connection
RE: Should latency numbers add up to total latency? - Hans Peter Augustesen - 07-12-2020
Here are some numbers from a duo session (Session Diagnostics & Stats):
1. person:
Total Latency: 22 ms
Audio Interface
Latency 4.2 ms
Input Jitter 0.48 ms
Output Jitter 0.42 ms
Frame Size 2.5 ms
Internet
Latency 13.0 ms
Jitter Queue 2.0
Jitter 0.7 ms
Audio Bw Rx 509 k
Audio Bw Tx 451 k
2. person:
Total Latency: 22 ms
Audio Interface
Latency 4.2 ms
Input Jitter 0.23 ms
Output Jitter 0.23 ms
Frame Size 2.5 ms
Internet
Latency 13.0 ms
Jitter Queue 4.2
Jitter 2.9 ms
Audio Bw Rx 430 k
Audio Bw Tx 525 k
---
As can be seen, both audio interface latency is 4.2 ms and internet latency is 13 ms.
Together it gives 21.4.
It is close to the 22 ms total latency.
But what about the other numbers?
Frame Size e.g. is a total of 5 ms.
It does not fit if these 5 ms are to be added.
And there are the other values as well.
So how does the whole calculation go up?
RE: Should latency numbers add up to total latency? - Hans Peter Augustesen - 07-25-2020
I'm also a bit confused, as it probably appears.
But in principle it is very simple.
Two people in a session have some latency in their audio interfaces.
Let’s say both people have 5 millisecond latency.
In total, it is 10 milliseconds.
In addition, the internet latency between the two people.
Let's say it's 40 milliseconds. Those 40 milliseconds must then be added to the 10 from the audio gear.
Result:
50 milliseconds total latency between those two persons.