[Freeswitch-users] PCMU fallback for T.38

[Gabriel Kuri]

err, no, I tried upgrading from r11000 to r12669 yesterday, but starting
seeing crashing, so I have a jira open. currently I'm back on r11000.

	http://jira.freeswitch.org/browse/FSCORE-338

Gabe


Brian West wrote:
> Are you on SVN trunk 12694?
> 
> /b
> 
> On Mar 20, 2009, at 4:28 PM, Gabriel Kuri wrote:
> 
>> hey folks, I'm trying to configure PCMU fallback for T.38.
>>
>> The originating endpoint (Linksys SPA-2102) sends an INVITE to FS with
>> G729 and PCMU in the sdp. the INVITE to the provider includes G729 and
>> PCMU as part of the sdp as well (absolute_codec_string=G729,PCMU) ...
>>
>> m=audio 16458 RTP/AVP 18 0 100 101
>> a=rtpmap:18 G729/8000
>> a=rtpmap:0 PCMU/8000
>> a=rtpmap:100 NSE/8000
>> a=fmtp:100 192-193
>> a=rtpmap:101 telephone-event/8000
>> a=fmtp:101 0-15
>> a=ptime:20
>>
>> once the FAX tone is detected on the PSTN side, FS receives a T.38
>> re-INVITE from the provider and FS sends back a 488/Not Acceptable
>> (proxy_media=false). at that point the provider than attempts fallback
>> to PCMU with another reINVITE ...
>>
>> m=audio 16816 RTP/AVP 0 101
>> a=rtpmap:0 PCMU/8000
>> a=rtpmap:101 telephone-event/8000
>> a=fmtp:101 0-15
>> a=ptime:20
>>
>> immediately after the PCMU reINVITE, FS closes the channel and the  
>> text
>> below is in the FS logs. given the SPA-2102 included PCMU in the
>> original INVITE, even though it was the second preferred codec,
>> shouldn't FS fallback to using PCMU if it was re-INVITEd with PCMU by
>> the provider? It seems like it's not passing the PCMU Re-INVITE back  
>> to
>> the endpoint (SPA-2102), since it originally negotiated G729 with the
>> SPA2102 as that was the 1st codec in the sdp, but trying to transcode
>> between the two (G729 and PCMU)?
>>
>>
>> 2009-03-20 01:19:58 [DEBUG] sofia_glue.c:2407  
>> sofia_glue_negotiate_sdp()
>> Audio Codec Compare [PCMU:0:8000]/[G729:18:8000]
>> 2009-03-20 01:19:58 [DEBUG] sofia_glue.c:2371  
>> sofia_glue_negotiate_sdp()
>> Set 2833 dtmf payload to 101
>> 2009-03-20 01:19:58 [DEBUG] sofia_glue.c:2407  
>> sofia_glue_negotiate_sdp()
>> Audio Codec Compare [telephone-event:101:8000]/[G729:18:8000]
>> 2009-03-20 01:19:58 [DEBUG] sofia_glue.c:2407  
>> sofia_glue_negotiate_sdp()
>> Audio Codec Compare [PCMU:0:8000]/[PCMU:0:8000]
>> 2009-03-20 01:19:58 [DEBUG] sofia_glue.c:1550
>> sofia_glue_tech_set_codec() Changing Codec from G729 to PCMU
>> 2009-03-20 01:19:58 [DEBUG] sofia_glue.c:1601
>> sofia_glue_tech_set_codec() Set Codec
>> sofia/cedarwireless.net/1XXXXXXXXXX at 1.1.1.1 PCMU/8000 20 ms 160  
>> samples
>> 2009-03-20 01:19:58 [DEBUG] sofia_glue.c:1811  
>> sofia_glue_activate_rtp()
>> Audio params are unchanged for sofia/cedarwireless.net/1XXXXXXXXXX at 1.1.1.1 
>> .
>> 2009-03-20 01:19:58 [DEBUG] sofia.c:2896 sofia_handle_sip_i_state()
>> Processing Reinvite
>> 2009-03-20 01:19:58 [DEBUG] sofia.c:2542 sofia_handle_sip_i_state()
>> Channel sofia/cedarwireless.net/1XXXXXXXXXX at 1.1.1.1 entering state
>> [completed]
>> 2009-03-20 01:19:58 [DEBUG] switch_core_io.c:655
>> switch_core_session_write_frame()
>> sofia/cedarwireless.net/1XXXXXXXXXX at 1.1.1.1 receive message
>> [SWITCH_MESSAGE_INDICATE_TRANSCODING_NECESSARY]
>> 2009-03-20 01:19:58 [ERR] mod_g729.c:145 switch_g729_decode() This  
>> codec
>> is only usable in passthrough mode!
>> 2009-03-20 01:19:58 [ERR] switch_core_io.c:723
>> switch_core_session_write_frame() Codec G.729 decoder error!
>>
>>
>> Thanks,
>>
>> Gabe
>>
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> 
> 
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