Think I found my answer... G.722 VoIP is typically carried in RTP <http://en.wikipedia.org/wiki/Real-time_Transport_Protocol> payload type 9. <http://en.wikipedia.org/wiki/G.722#cite_note-1> [2] Note that IANA <http://en.wikipedia.org/wiki/Internet_Assigned_Numbers_Authority> records the clock rate for type 9 G.722 as 8 kHz (instead of 16 kHz), RFC3551 <http://en.wikipedia.org/wiki/G.722#cite_note-2> [3] clarifies that this is due to a historical error and is retained in order to maintain backward compatibility. Consequently correct implementations represent the value 8,000 where required but encode and decode audio at 16 kHz. Whilst G.722 allows for bitrates of 64, 56 and 48 kbit/s, in practice, data is encoded at 64 kbit/s, with bits from the lower sub-band being used to encode auxiliary data. The greater the number of bits allocated to aux data, the lower the bit rate. Regards, Stephen From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of Stephen Dame Sent: Thursday, February 23, 2012 10:35 AM To: 'FreeSWITCH Users Help' Subject: [Freeswitch-users] G722 16k or 8k? Question on G722, trying to see if the quality of basic g.722 is much better than the standard g729 or g711. Looking at wiki docs. "G722 - G722 16kHz using default 20ms ptime. (multiples of 10)" However, when I connect to freeswitch using blink client I see G722/8000? I thought this would be 16000. I know when I connect using speex wb, it shows 16000. 2012-02-23 10:20:07.116606 [DEBUG] mod_sofia.c:750 Local SDP sofia/internal/1004@107.XX.XX.XX: v=0 o=FreeSWITCH 1329993171 1329993172 IN IP4 107.XX.XXX.XXX s=FreeSWITCH c=IN IP4 107.XX.XXX.XXX t=0 0 m=audio 17236 RTP/AVP 9 101 a=rtpmap:9 G722/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=silenceSupp:off - - - - a=ptime:20 a=sendrecv Shouldn't this be 16000? Thanks Stephen

On 02/23/2012 11:35 PM, Stephen Dame wrote:

Question on G722, trying to see if the quality of basic g.722 is much better than the standard g729 or g711.

The quality of G.711 is considerably better than G.729. The quality of G.722 is *massively* better than G.711. Why you can even spell things out, and be understood, without going "no F for Freddy, not S for stuff" all the time. :-)

Looking at wiki docs. “G722 - G722 16kHz using default 20ms ptime. (multiples of 10)”

However, when I connect to freeswitch using blink client I see G722/8000? I thought this would be 16000. I know when I connect using speex wb, it shows 16000.

2012-02-23 10:20:07.116606 [DEBUG] mod_sofia.c:750 Local SDP sofia/internal/1004@107.XX.XX.XX:

v=0

o=FreeSWITCH 1329993171 1329993172 IN IP4 107.XX.XXX.XXX

s=FreeSWITCH

c=IN IP4 107.XX.XXX.XXX

t=0 0

m=audio 17236 RTP/AVP 9 101

*a=rtpmap:9 G722/8000*

a=rtpmap:101 telephone-event/8000

a=fmtp:101 0-16

a=silenceSupp:off - - - -

a=ptime:20

a=sendrecv

Shouldn’t this be 16000?

Thanks

Stephen

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