Summary:	ASTERISK-29364: res_rtp_asterisk: standard deviation miscalculation
Reporter:	Kevin Harwell (kharwell)	Labels:
Date Opened:	2021-03-22 15:21:12	Date Closed:	2021-04-01 07:59:34
Priority:	Minor	Regression?	No
Status:	Closed/Complete	Components:	Resources/res_rtp_asterisk
Versions:	GIT 16.16.2 18.2.2	Frequency of Occurrence	Constant
Related Issues:
Environment:		Attachments:
Description:	The formula used to calculate standard deviation is not correct, and depending on the input excessively large numbers are seen. For example here's some output after I added the following logging to _calc_rxstamp_: {noformat} ast_log(LOG_VERBOSE, "calc_rxstamp - %f, %f, %f, %u\n", rtp->rxjitter, rtp->rtcp->normdev_rxjitter, rtp->rtcp->stdev_rxjitter, rtp->rtcp->rxjitter_count); {noformat} {noformat} calc_rxstamp - 0.000520, 0.000260, 0.000000, 2 calc_rxstamp - 0.000613, 0.000378, 0.000000, 3 calc_rxstamp - 0.000609, 0.000436, 0.000001, 4 calc_rxstamp - 0.000595, 0.000468, 0.000005, 5 calc_rxstamp - 0.000587, 0.000488, 0.000024, 6 calc_rxstamp - 0.000603, 0.000504, 0.000146, 7 calc_rxstamp - 0.000574, 0.000513, 0.001022, 8 calc_rxstamp - 0.000546, 0.000516, 0.008178, 9 calc_rxstamp - 0.000517, 0.000517, 0.073598, 10 calc_rxstamp - 0.000489, 0.000514, 0.735981, 11 calc_rxstamp - 0.000461, 0.000510, 8.095796, 12 calc_rxstamp - 0.000442, 0.000504, 97.149551, 13 calc_rxstamp - 0.000418, 0.000498, 1262.944167, 14 calc_rxstamp - 0.000401, 0.000492, 17681.218343, 15 calc_rxstamp - 0.000405, 0.000486, 265218.275142, 16 calc_rxstamp - 0.000381, 0.000480, 4243492.402266, 17 calc_rxstamp - 0.000370, 0.000474, 72139370.838520, 18 calc_rxstamp - 0.000357, 0.000468, 1298508675.093367, 19 calc_rxstamp - 0.000336, 0.000461, 24671664826.773975, 20 calc_rxstamp - 0.000320, 0.000454, 493433296535.479492, 21 calc_rxstamp - 0.000301, 0.000447, 10362099227245.070312, 22 calc_rxstamp - 0.000285, 0.000440, 227966182999391.562500, 23 calc_rxstamp - 0.000270, 0.000433, 5243222208986006.000000, 24 calc_rxstamp - 0.000258, 0.000426, 125837333015664144.000000, 25 calc_rxstamp - 0.000289, 0.000421, 3145933325391603712.000000, 26 calc_rxstamp - 0.000284, 0.000416, 81794266460181692416.000000, 27 calc_rxstamp - 0.000284, 0.000411, 2208445194424905629696.000000, 28 calc_rxstamp - 0.000314, 0.000408, 61836465443897356582912.000000, 29 calc_rxstamp - 0.000352, 0.000406, 1793257497873023248629760.000000, 30 {noformat} Similar output can be seen after hanging up a call when the following is in the dialplan: {noformat} exten => h,1,NoOp() same => n,Log(NOTICE, ${CHANNEL(rtcp,all_jitter)}) same => n,Log(NOTICE, ${CHANNEL(rtcp,all_rtt)}) {noformat} {noformat} [Mar 22 15:20:35] NOTICE[36116][C-00000001]: Ext. h:2 @ default:  minrxjitter=0.000584;maxrxjitter=0.007450;avgrxjitter=0.003584;stdevrxjitter=106709037996391588652335043005039379128254464.000000;reported_minjitter=11.000000;reported_maxjitter=11.000000;reported_avgjitter=11.000000;reported_stdevjitter=11.000000; [Mar 22 15:20:35] NOTICE[36116][C-00000001]: Ext. h:3 @ default:  minrtt=0.000000;maxrtt=0.000000;avgrtt=0.000000;stdevrtt=0.000000; {noformat}
Comments:	By: Friendly Automation (friendly-automation) 2021-04-01 07:59:35.666-0500 Change 15689 merged by Friendly Automation: res_rtp_asterisk: Fix standard deviation calculation [https://gerrit.asterisk.org/c/asterisk/+/15689|https://gerrit.asterisk.org/c/asterisk/+/15689] By: Friendly Automation (friendly-automation) 2021-04-01 08:43:11.226-0500 Change 15673 merged by George Joseph: res_rtp_asterisk: Fix standard deviation calculation [https://gerrit.asterisk.org/c/asterisk/+/15673|https://gerrit.asterisk.org/c/asterisk/+/15673] By: Friendly Automation (friendly-automation) 2021-04-01 08:43:23.597-0500 Change 15674 merged by George Joseph: res_rtp_asterisk: Fix standard deviation calculation [https://gerrit.asterisk.org/c/asterisk/+/15674|https://gerrit.asterisk.org/c/asterisk/+/15674]