[Freeswitch-users] Problems with G722 sample rate

[Steven Ayre]

The 16000 is probably there for interop with other devices that are
incorrect then, 8000 is the one you should use with FS.

-Steve




On 8 July 2013 18:04, Wesley Akio <wesleyakio at tuntscorp.com> wrote:

> Yeap, now I know, Anthony explained and pointed me to some literature...
> :/ "Historical reasons"...
>
> I'm playing with it right now and, in light of this information, it seems
> I missed something really obvious...
>
> Audiocodes has both G.722/8000 and G.722/16000 in the codecs list. At
> first I though it would vary the sample rate but testing it now it seems
> all it does is change the SDP, since using G.722/8000 results in:
> 2013-07-08 13:57:13.469291 [DEBUG] switch_ivr_play_say.c:1315 Codec
> Activated L16 at 16000hz 1 channels 20ms
>
> Will test a little bit further but it seems to be simpler than anticipated.
>
>
> Wesley Akio
> TuntsCorp.com
>
>
> On Mon, Jul 8, 2013 at 1:50 PM, Michael Jerris <mike at jerris.com> wrote:
>
>> It may seem crazy, but you have to use 8000 for g722.  If audiocodes is
>> really sending it as 16000 you need to report that to them.
>>
>> http://www.ietf.org/rfc/rfc3551.txt
>>
>> 4.5.2 G722
>>
>>    G722 is specified in ITU-T Recommendation G.722, "7 kHz audio-coding
>>    within 64 kbit/s".  The G.722 encoder produces a stream of octets,
>>    each of which SHALL be octet-aligned in an RTP packet.  The first bit
>>    transmitted in the G.722 octet, which is the most significant bit of
>>    the higher sub-band sample, SHALL correspond to the most significant
>>    bit of the octet in the RTP packet.
>>
>>    Even though the actual sampling rate for G.722 audio is 16,000 Hz,
>>    the RTP clock rate for the G722 payload format is 8,000 Hz because
>>    that value was erroneously assigned in RFC 1890 and must remain
>>    unchanged for backward compatibility.  The octet rate or sample-pair
>>    rate is 8,000 Hz.
>>
>>
>>
>> On Jul 8, 2013, at 12:17 PM, Wesley Akio <wesleyakio at tuntscorp.com>
>> wrote:
>>
>> Hi all,
>>
>> I'm having some trouble with G722 and AudioCodes HD310 in latest
>> 1.2-stable...
>>
>> The phone sends the SDP:
>> v=0
>> o=1000 946688278 946688278 IN IP4 192.168.0.108
>> s=-
>> c=IN IP4 192.168.0.108
>> t=0 0
>> m=audio 4000 RTP/AVP 9 0 8 18 101
>> a=rtpmap:9 G722/16000
>> a=rtpmap:0 PCMU/8000
>> a=rtpmap:8 PCMA/8000
>> a=rtpmap:18 G729/8000
>> a=fmtp:18 annexb=no
>> a=rtpmap:101 telephone-event/8000
>> a=fmtp:101 0-15
>>
>> But Freeswitch is prepared to accept only G722 at 8000 as can be seen in:
>>
>> [DEBUG] sofia_glue.c:5181 Audio Codec Compare
>> [G722:9:16000:20:64000]/[G722:9:8000:10:64000]
>>
>> For now I've changed the source to accept 16000 but according to Anthony,
>> as per the RFC, 8000 is the correct value.
>>
>> I've seen some conversations between Nandy Dagondon ans Steven Ayre but
>> I'm not sure if it is the same issue, nonetheless I could not find a
>> solution.
>>
>> has anyone faced a similar problem and found a viable solution?
>>
>>
>>
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>
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> http://www.freeswitchsolutions.com
>
> 
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