We're bridging webRTC to ISDN with FreeTDM and are experiencing frequent audio dropouts. On the webRTC end we've tried Opus and G.722 even with a client right next to the server. The effects are the same, so I'm fairly certain the problem is either on the ISDN end or inside FreeTDM. Unfortunately the only thing I could find that's related to the issue is a jitterbuffer underrun when this happens.

I've checked every troubleshooting hint Sangoma provides and played around with every config option I could find that might even be remotely related. But other than the buffer underruns I got nothing, though that feels more like a consequence rather than the reason. There are no frame errors/losses on the wanpipe devices (ifconfig) either.

Does anyone have an idea what else to check? (Freeswitch version is current master)




Jitterbuffer debug:
655: I: DEBUG len:5/10 i=533/1000 - g:537 c:533 b:0 - ts:2274276068/14214225/2274275908 - m:0(0.000000%) j:1.90% js:20/0 dr:-160/0
920: O: DEBUG 2274276068:14214225 0
907: DEBUG MISSING 2274276228:14214226 1533 2274276068 160 5 1
806: DEBUG OUT QUEUE: ------------
809: DEBUG 2274275108:14214219 r:1
809: DEBUG 2274275268:14214220 r:1
809: DEBUG 2274275428:14214221 r:1
809: DEBUG 2274275588:14214222 r:1
809: DEBUG 2274275748:14214223 r:1
811: DEBUG

812: DEBUG IN QUEUE: ------------
815: DEBUG 2274275908:14214224 r:1
815: DEBUG 2274276068:14214225 r:1
817: DEBUG


746: DEBUG OUT QUEUE EMPTY, SWAPPING
980: DEBUG PLC 1/10 1 160 2274276228:14214226
600: DEBUG TOO LATE !!! 2274276228


833: DEBUG JITTERBUFFER NOT READY: IGNORING FRAME
655: I: DEBUG len:5/10 i=534/1000 - g:0 c:533 b:1 - ts:2274276388/14214227/2274276228 - m:1(0.100000%) j:1.90% js:20/0 dr:-160/0
655: I: DEBUG len:5/10 i=535/1000 - g:0 c:534 b:1 - ts:2274276548/14214228/2274276228 - m:1(0.100000%) j:1.90% js:20/0 dr:-160/0
833: DEBUG JITTERBUFFER NOT READY: IGNORING FRAME
655: I: DEBUG len:5/10 i=536/1000 - g:0 c:535 b:1 - ts:2274276708/14214229/2274276228 - m:1(0.100000%) j:1.90% js:20/0 dr:-160/0
833: DEBUG JITTERBUFFER NOT READY: IGNORING FRAME
655: I: DEBUG len:5/10 i=537/1000 - g:0 c:536 b:1 - ts:2274276868/14214230/2274276228 - m:1(0.100000%) j:1.90% js:20/0 dr:-160/0
833: DEBUG JITTERBUFFER NOT READY: IGNORING FRAME
655: I: DEBUG len:5/10 i=538/1000 - g:0 c:537 b:1 - ts:2274277028/14214231/2274276228 - m:1(0.100000%) j:1.90% js:20/0 dr:-160/0
920: O: DEBUG 2274276388:14214227 0