Ping value calculation in Jamulus

[RepZ97]

How does Jamulus calculate the ping value between the client and the server ? Which protocols are being used to gather the network latency information ? Is it icmpv6 ? Thank you.

[dcorson-ticino-com]

The client does not calculate the ping time to the servers, it measures the ping time using UDP messages.

[RepZ97]

@dcorson-ticino-com Yes definitely we have to include audio delays as well. I was hoping calculate them seperately after calculating the network delay. Thank you for the idea, and actually.. I might try that to get the absolute end-to-end latency. A very good suggestion. Thank you.

[RepZ97]

@hoffie Sure thing. I'd be happy to keep you updated in this thread for future results. Thank you as well for the wireshark dissector suggestion. I'll check that out.

[RepZ97]

@passing Thank you for the information. Much appreciated.

[dcorson-ticino-com]

@dcorson-ticino-com I was hoping calculate them seperately after calculating the network delay

Not sure how you can calculate anything in a non-deterministic system. You may be able to calculate the theoretical minimum, if you know all the characteristics of the parts of the system, but that is not the real world. Measurement is also subject to the vagarities of the non-deterministic system, but at least it is real and true for the actual case. If you have the equipment, measurement is also probably much faster to do.

[RepZ97]

@dcorson-ticino-com I was hoping calculate them seperately after calculating the network delay

Not sure how you can calculate anything in a non-deterministic system. You may be able to calculate the theoretical minimum, if you know all the characteristics of the parts of the system, but that is not the real world. Measurement is also subject to the vagarities of the non-deterministic system, but at least it is real and true for the actual case. If you have the equipment, measurement is also probably much faster to do.

Well, at least we can calculate the theoretical values for certain certain parameters and conditions (Not all of them. With a margin for indeterminable and negligable delays) and then compare them with our experimental results for those specific parameters and conditions. See the variation of the results against the theoretical values and get a some idea about the standard deviation and what not. Kind of like evaluating the system to see where we can improve.

[RepZ97]

Can anyone comment on how the Jamulus client software actually calculate the total audio delay (not the ping) which is displayed on its interface ?

[pljones]

Jitter buffers + ping, as far as I'm aware.

[dcorson-ticino-com]

See: CClient::EstimatedOverallDelay in client.cpp

[RepZ97]

@pljones and @dcorson-ticino-com Thank you. I will check these out.