[iptv-users] Causes of jitter
frnkblk at iname.com
Sat Dec 4 17:40:44 EST 2010
One of our Calix rings is experiencing some very short video freezing (no
perceptible interruption in the audio). It appears to happen on all Calix
nodes in that ring and appears to be regardless of channel. Sometimes it's
worse (almost unwatchable) and sometimes we get no complaints for days.
Selective analysis of customer Calix ports counters show clean or very few
errors, definitely nothing that I can attribute to physical plant.
I watched one hour of programming Friday morning at a customer and counted
15 freezing events, all of them but one very short. We don't have any
formal testing gear (yet), but a borrowed JDSU T-Berd is showing occasional
jitter (up to 18 msec, sometimes 5 msec) and both the T-Berd and TS-Reader
are showing identical Continuity Counter counter values.
Sometimes the freezing is accompanied by the CC going up by two (one for
audio, one for video), other times the freezing doesn't have any change to
CC, and sometimes the CC goes up and we don't perceive any freezing.
I would like any and all input on:
a) possible sources of the freezing
b) test tools on both the network and post-STB that can record the issue and
underlying issue (i.e. jitter or packet loss). Ineoquest has a probe that
can be plugged into the RCA or HDMI output and provide some analysis)
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