[SOLVED]Jitter Buffer UnderRun

Started by earthtoobi, March 22, 2011, 10:03:54 PM

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earthtoobi

have setup vitelity as service provider to place international calls. i noticed that the call quality at destination was fine but the call quality at my end was choppy. after the call, i looked at the RTP statistics and i see values for
UnderRun (a value like "24850").

Have a 7Mbps Download and 0.5Mbps Upload internet connection.

was wondering if this is related to not setting up portforward OR internet connection OR ServiceProvider

earthtoobi

Attached is the RTP Statistics with Under Run

LeftRight

#2
Jitter buffer underrun is not necessarily the reason causing your call quality issue. Underruncould be due to 1) silence suppression from the other party, 2) large network jitter, 3) packet loss. Your RTP statistics shows almost no packet loss, so your network might be just fine.

Instead of looking at SP1 & SP2 statistics, which accumulates the number over all the calls, you might look into call status when you experience bad voice quality. It has much more details regarding one particular call, and you can send it to OBi support team for an analysis.

earthtoobi

Attached is the call status as it was occurring.

LeftRight

#4
OK, from the figures shown in your call status, the jitter buffer underrun is surely caused by silence suppression. the ratio of packets received and sent is roughly about 50%, which means the callee suppresses silence 50% of time.

You have very little packet loss (only 1 packet), but did experience some network jitter (480+ ms), which caused some packet dropped (6%). This could degrade your voice quality by some level.

Usually, silence suppression should not degrade voice quality, unless there is a high level of background noise on the callee side. You might initiate another call but with callee at a relatively quite place, just to confirm silence suppression does not affect your call.

Also, you can try to call a different destination (local or international), and check on quality... after all, VoIP cannot eliminate network impairments, but mitigate it at its best ...

earthtoobi

Here is another call status information today.
call quality on my side was good.
but the other party says my voice breaks big time.

earthtoobi

Used G729 codec(to save on bandwidth) to make an International call to a landline through vitelity (mine is  512Kbps Upstream).
Attached is the screen shot captured for a call made for 30 mins. i can hear the other party while they are hearing choppy audio from time to time.

earthtoobi

Closing this since i don't see these issues now and if any are related to the provider