Re: skew, delta and jitter in wireshark VOIP->analyse

[nangergong <nangergong () gmail com>]

Maybe I need to add:

when I use G711 or G729, wireshark can show the jitter/skew/delta

and if I use iLBC, wireshark can show the codec name (iLBC) bandwidth,
packet loss, but skew, delta and jitter shown in wireshark VOIP-Analysis GUI
are all 0


On Wed, Feb 9, 2011 at 5:30 PM, Anders Broman <anders.broman () ericsson com>wrote:

>  Hi,
> It might depend on the version you are using, the RTP analysis needs to
> know the sampling rate (8KHz normally for voice) and the sampling
> rate is only known for the fixed payload types and a set of dynamic
> ones(hard coded list), in newer WS versions the sampling rate is extracted
> from SDP.
> I don't remember if it's part of 1.4.x or if you have to use a development
> version.
> Regards
> Anders
>
>  ------------------------------
> *From:* wireshark-users-bounces () wireshark org [mailto:
> wireshark-users-bounces () wireshark org] *On Behalf Of *nangergong
> *Sent:* den 9 februari 2011 17:37
> *To:* Community support list for Wireshark
>
> *Subject:* Re: [Wireshark-users] skew, delta and jitter in wireshark
> VOIP->analyse
>
> thanks
>
> BTW, when I use iLBC codec for audio VOIP calls, I noticed that the skew,
> delta and jitter shown in wireshark VOIP-Analysis GUI are all 0, what is the
> reason for this? Does this mean that wireshark can't analyze iLBC codec?
>
>
>
>
>
> On Wed, Feb 9, 2011 at 2:04 PM, Anders Broman <anders.broman () ericsson com>wrote:
>
> > -----Original Message-----
> > From: wireshark-users-bounces () wireshark org [mailto:
> > wireshark-users-bounces () wireshark org] On Behalf Of Giles Coochey
> > Sent: den 9 februari 2011 14:48
> > To: wireshark-users () wireshark org
> > Subject: Re: [Wireshark-users] skew, delta and jitter in wireshark
> > VOIP->analyse
> >
> > On 09/02/2011 14:37, nangergong wrote:
> > > > Hi, all,
> > > >
> > > >   What is the difference between skew, delta and jitter in a voip
> > stream?
> > > >   I only know the impact of jitters on voip streams, what are the
> > > > impacts of skew and delta on VOIP streaming quality?
> > > >
> > > >   Thank you!
> > > Not sure if my understanding is correct... skew is absolute jitter based
> > on comparison on the first packet(s).
> > > delta is what I understand to be latency, or delay.
> > >
> > > --
> > > Best Regards,
> > >
> > > Giles Coochey
> > See
> > http://books.google.com/books?id=OM7YJAy9_m8C&pg=PA175&lpg=PA175&dq=RTP+skew&source=bl&ots=hUOESKrWB4&sig=F2cjXTyonrfi5R7pgKjuHRli4SA&hl=sv&ei=np1STe-PFIfLswbL7bjyBg&sa=X&oi=book_result&ct=result&resnum=10&ved=0CEQQ6AEwCQ#v=onepage&q=RTP%20skew&f=false
> >
> >
> >
> >
> >
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