Jitter and the TSP Media Driver

[dvowell]

Hi all,

I am currently investigating an issue with a third-party CTI application that terminates the media using the Cisco TSP Media Driver. Intermittently, the customer experiences poor quality audio where a popping sound can be heard over the audio. After a lot of investigation, it seems that the impacted calls have a higher level of jitter than the good calls. By higher, I don't mean excessive jitter, as it is less than 20ms, it is just more than the good calls which are typically <2  msec. When one of the calls with the poor audio is transferred to an IP Phone, the audio is fine.

My question is, does the TSP Media Driver implement any form of de-jitter buffering like the IP Phones or is this the responsibility of the application?

[DavidStaudt]

The TSP media driver is pretty simple, in that it simply transfers packets of audio bytes to/from the application - any processing of that audio would be up to the app.

If the poor voice quality is experienced by users listening to audio coming from the application, that sounds like the application (meaning  is perhaps having difficulty consistently providing audio packets smoothly on time - especially if there is significant simultaneous load and/or CPU resources are oversubscribed.  

[dvowell]

Hi David, thanks for the feedback. We are continuing to investigate.