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
