Johan/Olle, Apologies for the delay in replying; I have been away from the office for a day or so. Thank you for your suggestions: extremely useful. We actually went with an external test using the simple Audacity approach outlined in Item 2 below. During trials this week the customer was satisfied with this approach. Thanks again and I hope you have a merry Christmas and a happy New Year... Tim -----Original Message----- From: pjsip [mailto:pjsip-bounces@xxxxxxxxxxxxxxx] On Behalf Of JOHAN LANTZ Sent: 05 December 2012 12:20 To: pjsip at lists.pjsip.org Subject: Re: Measuring Voice Latency Hi Tim I will try to give you some suggestions from the top of my head. 1. As a purely static approach you can estimate this by looking at the playback and recording buffer sizes. Adding receiver jitter buffer medium values and expected NW transport time, it should give you a theoretical idea. It is also good to get familiar with these params since if latency is a key thing for you you might want to optimize these buffers later on to make them fit your use case and network conditions. 2. If you are not looking for auto generated statistics a very simple approach is just to use Audacity and put the two phones in the same room and mute one of them. Make a noise spike. You will then see this spike in audacity and you will also see the corresponding spike when its played back in the receiving phone. After that you can just manually measure the time between the 2 spikes and you will get an idea on the latency. Its good for empirical testing if you do not need automation. 3. Maybe there are already some good tools in pjsip that I have not tried but you should be able to do a lot looking at for instance RTP sequence numbers. If the timing is correct between the two devices I think you can quite easily parse a log file to see when timestamp A was received in B. However doing this you have to take into consideration when in the audio flow you are looking at the timestamp since the buffers will affect this value as well. If you just want to look at network latency Wireshark with the clients in the same computer should also give you an idea. There are probably other more sophisticated ways to do this as well. /Johan ________________________________ Este mensaje se dirige exclusivamente a su destinatario. Puede consultar nuestra pol?tica de env?o y recepci?n de correo electr?nico en el enlace situado m?s abajo. This message is intended exclusively for its addressee. We only send and receive email on the basis of the terms set out at: http://www.tid.es/ES/PAGINAS/disclaimer.aspx _______________________________________________ Visit our blog: http://blog.pjsip.org pjsip mailing list pjsip at lists.pjsip.org http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org The information contained within this e-mail and any files attached to this e-mail is private and in addition may include commercially sensitive information. The contents of this e-mail are for the intended recipient only and therefore if you wish to disclose the information contained within this e-mail or attached files, please contact the sender prior to any such disclosure. If you are not the intended recipient, any disclosure, copying or distribution is prohibited. Please also contact the sender and inform them of the error and delete the e-mail, including any attached files from your system. Cassidian Limited, Registered Office : Quadrant House, Celtic Springs, Coedkernew, Newport, NP10 8FZ Company No: 04191036 http://www.cassidian.com
