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RE: [AVT] questions about jitter



RFC 3550 states that the jitter SHOULD be calculated continuously as each
data packet i is received. The standard deviation is basically a block calculation,
although it can be computed recursively using buffers.

The method proposed in the RFC is a simple 1-lag IIR smoothing filter
with an empirically set decay time. Although I personally
wouldn't have used the wording "optimal first-order estimator",
it certainly is the most straightforward way to compute a time-averaged
jitter value.

In any case, why do you want to compute PDV if your
problem is packet loss rate ?  The jitter is an additional characteristic,
and shouldn't directly effect "network quality" (e.g. perceived audio quality)
unless there are large PDV swings, causing jitter buffer over- or under-flow
and hence "internal" packet loss.

Y(J)S


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