I know that 125 µs relates to the sample period, which is however identical to
the frame size in case of G.711 IMHO.
Could you provide your reference concerning the 5 ms definition?
Thanks, Albrecht
________________________________
From: Aneesh Naik [mailto:[EMAIL PROTECTED]
Sent: Montag, 22. September 2008 14:45
To: Schwarz Albrecht
Cc: Sachin Rastogi; [email protected]
Subject: Re: [Sip-implementors] Should 'ptime' value be multiple of 5
or 10
125 µs is not the frame size of G.711. It is the time sampling rate.
8000 samples in 1 sec.
1 sample in 125 µs.
Number of such samples are combined to form a frame of data.
This frame size for G.711 is 5ms.
Hope this clears your understanding.
Thanks,
Aneesh
On Mon, Sep 22, 2008 at 5:43 PM, Schwarz Albrecht <[EMAIL PROTECTED]>
wrote:
> > The frame size for g.711 is 5ms
G.711 has a frame size of 125 µs in my understanding.
See ITU-T G.711.
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On
> Behalf Of Sachin Rastogi
> Sent: Montag, 22. September 2008 13:45
> To: Aneesh Naik
> Cc: [email protected]
> Subject: Re: [Sip-implementors] Should 'ptime' value be
> multiple of 5 or 10
>
> Thanks Aneesh,Alex for quick reply.
>
>
> Sachin
>
> On Mon, Sep 22, 2008 at 3:03 PM, Aneesh Naik
> <[EMAIL PROTECTED]> wrote:
>
> > Yes, as explained by alex the ptime depend on the frame
size...
> > The frame size for g.711 is 5ms, for g.729 is 10ms and for
> g.723 it is
> > 30 ms.
> > So the ptime for 711 and 729 can be 10, 20, 30... and for
> 723 it can
> > be 30,60....
> >
> > -Aneesh
> >
> > On Mon, Sep 22, 2008 at 1:50 PM, Alex Balashov
> > <[EMAIL PROTECTED]
> > >wrote:
> >
> > > There are no drafts or recommendations mandating that
ptime be a
> > > particular value because the desired packetisation
duration is
> > > closely related to the frame size and other
> characteristics of particular codecs.
> > >
> > > However, almost no media gateway equipment out there will
support
> > > anything other than the usual 10-30 ms for the usual
suspects -
> > > G.711u/A, G.729A, etc.
> > >
> > > There are certain recommendations or mandates for ptime
> values based
> > > on particular codecs. For instance, 20 ms is recommended
> when using
> > > Speex
> > >
(http://www.speex.org/docs/manual/speex-manual/node14.html):
> > >
> > > ---
> > >
> > > 4.1.1. Registration of media type audio/speex
> > >
> > > Media type name: audio
> > >
> > > Media subtype name: speex
> > >
> > > Required parameters:
> > >
> > > None
> > >
> > > Optional parameters:
> > >
> > > ptime: see RFC 4566. SHOULD be a multiple of 20
msec.
> > >
> > > maxptime: see RFC 4566. SHOULD be a multiple of 20
msec.
> > >
> > >
> > >
> > > Sachin Rastogi wrote:
> > >
> > > > Hi All,
> > > > Is there any rfc/draft or recommendation which suggests
> that 'ptime'
> > > > value should multiple of 5 or 10? Can I use 'ptime'
> value as 11 or
> > > > 12
> > or
> > > 18
> > > > or 19?
> > > >
> > > >
> > > >
> > > > Thanks
> > > > Sachin Rastogi
> > > > _______________________________________________
> > > > Sip-implementors mailing list
> > > > [email protected]
> > > >
>
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
> > >
> > >
> > > --
> > > Alex Balashov
> > > Evariste Systems
> > > Web : http://www.evaristesys.com/
> > > Tel : (+1) (678) 954-0670
> > > Direct : (+1) (678) 954-0671
> > > Mobile : (+1) (706) 338-8599
> > > _______________________________________________
> > > Sip-implementors mailing list
> > > [email protected]
> > >
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
> > >
> >
> >
> >
> > --
> > Aneesh
> > _______________________________________________
> > Sip-implementors mailing list
> > [email protected]
> >
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
> >
> _______________________________________________
> Sip-implementors mailing list
> [email protected]
>
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>
--
Aneesh
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
