[Asterisk-Users] Re: Audio flutter on OH323 output?

[Tony Mountifield]

In article <d6ft7h$dsd$1 at softins.clara.co.uk>, I wrote:
> In article <428B6974.7080305 at inaccessnetworks.com>,
> Michael Manousos <manousos at inaccessnetworks.com> wrote:
> > 
> > Can you get an ethereal trace on a call with that problem?
> > Run an RTP analysis on the captured stream (Tools Menu) and save
> > the contents of the RTP packets in audio files. Then check if
> > the playback of these files is normal or not.
> 
> Aha, sounds like Ethereal has even more clever features - I didn't
> know it could do that.
> 
> Fortunately, I've been running a continuous tcpdump capture on the
> Asterisk box of the traffic between it and the switch. I'll see
> what Ethereal thinks of it.

Hi Michael,

I've now done some RTP analysis of affected streams, and have found that
the times when we get the audio flutter correspond with parts of the
analysis showing repeated packets in the RTP stream. This only happens
on the outgoing stream; the incoming stream from the switch is perfect.

When a packet is repeated, it is identical to the previous and occurs
about 7 to 14 microsec after, as if something in the software has decided
to send the packet twice in immediate succession.

I've pasted below an extract from the CVS file saved from the RTP
stream analysis. I also saved the payload (pity it converts it to uLaw
instead of saving it in the stream's native format) and listened to it
to confirm the periods of distortion.

I would assume the problem is somewhere in the depths of openh323, but
any pointers in the right direction would be appreciated!

Cheers
Tony

Here is the CSV extract:

Packet,Sequence,Delay (s),Jitter (s),Marker,Status,Date,Length
144209,17353,0.020000,0.000003,,[ Ok ],05/17/2005 17:05:48.420,214
144225,17354,0.020006,0.000003,,[ Ok ],05/17/2005 17:05:48.440,214
144226,17354,0.000007,0.000003,,Wrong sequence nr.,05/17/2005 17:05:48.440,214
144244,17355,0.019987,0.000004,,[ Ok ],05/17/2005 17:05:48.460,214
144260,17356,0.019998,0.000004,,[ Ok ],05/17/2005 17:05:48.480,214
144261,17356,0.000008,0.000004,,Wrong sequence nr.,05/17/2005 17:05:48.480,214
144276,17357,0.019991,0.000004,,[ Ok ],05/17/2005 17:05:48.500,214
144296,17358,0.019992,0.000004,,[ Ok ],05/17/2005 17:05:48.520,214
144298,17358,0.000009,0.000005,,Wrong sequence nr.,05/17/2005 17:05:48.520,214
144313,17359,0.019990,0.000005,,[ Ok ],05/17/2005 17:05:48.540,214
144329,17360,0.020000,0.000005,,[ Ok ],05/17/2005 17:05:48.560,214
144349,17361,0.019992,0.000005,,[ Ok ],05/17/2005 17:05:48.580,214
144368,17362,0.020003,0.000005,,[ Ok ],05/17/2005 17:05:48.600,214
144369,17362,0.000006,0.000005,,Wrong sequence nr.,05/17/2005 17:05:48.600,214
144383,17363,0.019990,0.000005,,[ Ok ],05/17/2005 17:05:48.620,214
144401,17364,0.019995,0.000005,,[ Ok ],05/17/2005 17:05:48.640,214
144417,17365,0.020001,0.000005,,[ Ok ],05/17/2005 17:05:48.660,214
144432,17366,0.019994,0.000005,,[ Ok ],05/17/2005 17:05:48.680,214
144452,17367,0.019997,0.000005,,[ Ok ],05/17/2005 17:05:48.700,214
144469,17368,0.020002,0.000005,,[ Ok ],05/17/2005 17:05:48.720,214
144486,17369,0.019998,0.000005,,[ Ok ],05/17/2005 17:05:48.740,214
144487,17369,0.000008,0.000005,,Wrong sequence nr.,05/17/2005 17:05:48.740,214
144506,17370,0.019985,0.000005,,[ Ok ],05/17/2005 17:05:48.760,214
144523,17371,0.019999,0.000005,,[ Ok ],05/17/2005 17:05:48.780,214
144540,17372,0.020005,0.000005,,[ Ok ],05/17/2005 17:05:48.800,214
144559,17373,0.019992,0.000005,,[ Ok ],05/17/2005 17:05:48.820,214
144560,17373,0.000008,0.000005,,Wrong sequence nr.,05/17/2005 17:05:48.820,214
144576,17374,0.019988,0.000006,,[ Ok ],05/17/2005 17:05:48.840,214
144577,17374,0.000007,0.000006,,Wrong sequence nr.,05/17/2005 17:05:48.840,214
144592,17375,0.019992,0.000006,,[ Ok ],05/17/2005 17:05:48.860,214
144593,17375,0.000008,0.000006,,Wrong sequence nr.,05/17/2005 17:05:48.860,214
144610,17376,0.019987,0.000007,,[ Ok ],05/17/2005 17:05:48.880,214
144627,17377,0.019997,0.000006,,[ Ok ],05/17/2005 17:05:48.900,214
144628,17377,0.000008,0.000006,,Wrong sequence nr.,05/17/2005 17:05:48.900,214
144642,17378,0.019989,0.000007,,[ Ok ],05/17/2005 17:05:48.920,214
144661,17379,0.019997,0.000007,,[ Ok ],05/17/2005 17:05:48.940,214
144678,17380,0.020004,0.000006,,[ Ok ],05/17/2005 17:05:48.960,214
144679,17380,0.000009,0.000007,,Wrong sequence nr.,05/17/2005 17:05:48.960,214
144695,17381,0.019988,0.000007,,[ Ok ],05/17/2005 17:05:48.980,214
144696,17381,0.000007,0.000007,,Wrong sequence nr.,05/17/2005 17:05:48.980,214
144713,17382,0.019982,0.000008,,[ Ok ],05/17/2005 17:05:49.000,214
144732,17383,0.020002,0.000007,,[ Ok ],05/17/2005 17:05:49.020,214
144733,17383,0.000008,0.000007,,Wrong sequence nr.,05/17/2005 17:05:49.020,214
144747,17384,0.019989,0.000008,,[ Ok ],05/17/2005 17:05:49.040,214
144768,17385,0.020000,0.000007,,[ Ok ],05/17/2005 17:05:49.060,214
144769,17385,0.000007,0.000007,,Wrong sequence nr.,05/17/2005 17:05:49.060,214
144784,17386,0.019986,0.000007,,[ Ok ],05/17/2005 17:05:49.080,214
144801,17387,0.020001,0.000007,,[ Ok ],05/17/2005 17:05:49.100,214
144802,17387,0.000008,0.000007,,Wrong sequence nr.,05/17/2005 17:05:49.100,214
144820,17388,0.019987,0.000007,,[ Ok ],05/17/2005 17:05:49.120,214
144836,17389,0.020001,0.000007,,[ Ok ],05/17/2005 17:05:49.140,214
144852,17390,0.019994,0.000007,,[ Ok ],05/17/2005 17:05:49.160,214
144854,17390,0.000008,0.000007,,Wrong sequence nr.,05/17/2005 17:05:49.160,214
144872,17391,0.019990,0.000007,,[ Ok ],05/17/2005 17:05:49.180,214
144891,17392,0.019995,0.000007,,[ Ok ],05/17/2005 17:05:49.200,214
144907,17393,0.019999,0.000007,,[ Ok ],05/17/2005 17:05:49.220,214
144926,17394,0.019996,0.000007,,[ Ok ],05/17/2005 17:05:49.240,214
144942,17395,0.020001,0.000006,,[ Ok ],05/17/2005 17:05:49.260,214
144958,17396,0.019993,0.000006,,[ Ok ],05/17/2005 17:05:49.280,214
144976,17397,0.019999,0.000006,,[ Ok ],05/17/2005 17:05:49.300,214
144992,17398,0.019995,0.000006,,[ Ok ],05/17/2005 17:05:49.320,214
145008,17399,0.019999,0.000006,,[ Ok ],05/17/2005 17:05:49.340,214
145026,17400,0.019996,0.000005,,[ Ok ],05/17/2005 17:05:49.360,214
145042,17401,0.019999,0.000005,,[ Ok ],05/17/2005 17:05:49.380,214
145059,17402,0.020001,0.000005,,[ Ok ],05/17/2005 17:05:49.400,214
145079,17403,0.019993,0.000005,,[ Ok ],05/17/2005 17:05:49.420,214
145097,17404,0.020003,0.000005,,[ Ok ],05/17/2005 17:05:49.440,214
145098,17404,0.000007,0.000005,,Wrong sequence nr.,05/17/2005 17:05:49.440,214
145113,17405,0.019987,0.000006,,[ Ok ],05/17/2005 17:05:49.460,214
145131,17406,0.019996,0.000005,,[ Ok ],05/17/2005 17:05:49.480,214
145147,17407,0.019997,0.000005,,[ Ok ],05/17/2005 17:05:49.500,214
145163,17408,0.020002,0.000005,,[ Ok ],05/17/2005 17:05:49.520,214
145182,17409,0.019993,0.000005,,[ Ok ],05/17/2005 17:05:49.540,214
145198,17410,0.020000,0.000005,,[ Ok ],05/17/2005 17:05:49.560,214
145215,17411,0.019997,0.000005,,[ Ok ],05/17/2005 17:05:49.580,214
145235,17412,0.019998,0.000005,,[ Ok ],05/17/2005 17:05:49.600,214
145251,17413,0.019999,0.000004,,[ Ok ],05/17/2005 17:05:49.620,214
145267,17414,0.019996,0.000004,,[ Ok ],05/17/2005 17:05:49.640,214
145287,17415,0.019999,0.000004,,[ Ok ],05/17/2005 17:05:49.660,214
145303,17416,0.019996,0.000004,,[ Ok ],05/17/2005 17:05:49.680,214
145320,17417,0.020000,0.000004,,[ Ok ],05/17/2005 17:05:49.700,214
145321,17417,0.000008,0.000004,,Wrong sequence nr.,05/17/2005 17:05:49.700,214
145341,17418,0.019989,0.000005,,[ Ok ],05/17/2005 17:05:49.720,214
145342,17418,0.000007,0.000005,,Wrong sequence nr.,05/17/2005 17:05:49.720,214
145358,17419,0.019992,0.000005,,[ Ok ],05/17/2005 17:05:49.740,214
145373,17420,0.019998,0.000005,,[ Ok ],05/17/2005 17:05:49.760,214
145392,17421,0.019995,0.000005,,[ Ok ],05/17/2005 17:05:49.780,214
145409,17422,0.019996,0.000005,,[ Ok ],05/17/2005 17:05:49.800,214
145425,17423,0.019999,0.000004,,[ Ok ],05/17/2005 17:05:49.819,214
145444,17424,0.019995,0.000005,,[ Ok ],05/17/2005 17:05:49.839,214
145461,17425,0.020002,0.000004,,[ Ok ],05/17/2005 17:05:49.859,214
145462,17425,0.000008,0.000005,,Wrong sequence nr.,05/17/2005 17:05:49.860,214
145476,17426,0.019986,0.000005,,[ Ok ],05/17/2005 17:05:49.879,214
145497,17427,0.020000,0.000005,,[ Ok ],05/17/2005 17:05:49.899,214
145498,17427,0.000008,0.000005,,Wrong sequence nr.,05/17/2005 17:05:49.899,214
145513,17428,0.019987,0.000006,,[ Ok ],05/17/2005 17:05:49.919,214
145531,17429,0.019998,0.000005,,[ Ok ],05/17/2005 17:05:49.939,214
145532,17429,0.000009,0.000006,,Wrong sequence nr.,05/17/2005 17:05:49.939,214
145550,17430,0.019986,0.000006,,[ Ok ],05/17/2005 17:05:49.959,214
145569,17431,0.020006,0.000006,,[ Ok ],05/17/2005 17:05:49.979,214
145570,17431,0.000008,0.000006,,Wrong sequence nr.,05/17/2005 17:05:49.979,214
145584,17432,0.019983,0.000007,,[ Ok ],05/17/2005 17:05:49.999,214
145605,17433,0.020002,0.000007,,[ Ok ],05/17/2005 17:05:50.019,214
145606,17433,0.000008,0.000007,,Wrong sequence nr.,05/17/2005 17:05:50.019,214
145621,17434,0.019984,0.000007,,[ Ok ],05/17/2005 17:05:50.039,214
145638,17435,0.020003,0.000007,,[ Ok ],05/17/2005 17:05:50.059,214
145639,17435,0.000008,0.000007,,Wrong sequence nr.,05/17/2005 17:05:50.059,214
145656,17436,0.019984,0.000008,,[ Ok ],05/17/2005 17:05:50.079,214
145673,17437,0.019997,0.000007,,[ Ok ],05/17/2005 17:05:50.099,214
145689,17438,0.019998,0.000007,,[ Ok ],05/17/2005 17:05:50.119,214
145708,17439,0.019999,0.000007,,[ Ok ],05/17/2005 17:05:50.139,214
145725,17440,0.019997,0.000006,,[ Ok ],05/17/2005 17:05:50.159,214
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org