Video Calls Using Cisco Phones Are 176×144(QCIF) And 15FPS Both Ways

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Asterisk Users 3 Comments

We are experiencing an issue with our Cisco 9971 and 8945 phones where H264
video calls are connecting at 176×144 resolution instead of 640×480. Soft clients can connect at higher resolutions and the 9971 can even receive video at a higher resolution (although it still sends 176×144).

I contacted one of the developers and he suggested the passthrough of SDP
attributes is not working correctly. Has anyone else experienced this problem? We’re running Asterisk 11.8.1.

Below are the video parts of the sip debug for one of the phones during a video call. Should I be seeing the “a=imageattr” in the SIP OK message?

<--- SIP read from UDP:10.168.154.71:5060 --->
INVITE sip:7872@10.162.26.15;user=phone SIP/2.0
Via: SIP/2.0/UDP 10.168.154.71:5060;branch=z9hG4bK1182b2d3
From: “Shawn Hughes”
Call-ID: 20bbc0df-35ef000a-453db49e-67cd30f1@10.168.154.71
Max-Forwards: 70
Date: Fri, 28 Mar 2014 13:51:41 GMT
CSeq: 102 INVITE
User-Agent: Cisco-CP8945/9.4.1
Contact: ;video Authorization: Digest username=”7871″,realm=”asterisk”,uri=”
sip:7872@10.162.26.15
;user=phone”,response=”f51a7522b01c90b81509d2274e9b69bb”,nonce=”5b43e5a6″,algorithm=MD5
Expires: 180
Accept: application/sdp Allow:
ACK,BYE,CANCEL,INVITE,NOTIFY,OPTIONS,REFER,REGISTER,UPDATE,SUBSCRIBE,INFO
Supported:
replaces,join,sdp-anat,norefersub,resource-priority,extended-refer,X-cisco-callinfo,X-cisco-serviceuri,X-cisco-escapecodes,X-cisco-service-control,X-cisco-srtp-fallback,X-cisco-monrec,X-cisco-config,X-cisco-sis-6.0.2,X-cisco-xsi-8.5.1
Allow-Events: kpml,dialog Content-Length: 685
Content-Type: application/sdp Content-Disposition: session;handling=optional

v=0
o=Cisco-SIPUA 27778 0 IN IP4 10.168.154.71
s=SIP Call t=0 0
m=audio 10032 RTP/AVP 0 8 18 102 9 116 101
c=IN IP4 10.168.154.71
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no a=rtpmap:102 L16/16000
a=rtpmap:9 G722/8000
a=rtpmap:116 iLBC/8000
a=fmtp:116 mode a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=sendrecv m=video 10034 RTP/AVP 97
c=IN IP4 10.168.154.71
b=TIAS:2000000
a=rtpmap:97 H264/90000
a=fmtp:97
profile-level-idB8014;packetization-mode=0;level-asymmetry-allowed=1;max-mbps6000;max-fs00
a=imageattr:97 send [xd0,yH0] [xd0,y60] [x52,y(8] [x6,y4]
recv [xd0,yH0]
a=sendrecv
<------------->
— (19 headers 24 lines) –

3 thoughts on - Video Calls Using Cisco Phones Are 176×144(QCIF) And 15FPS Both Ways

  • Matt Rabbitt wrote:

    It looks as though the passthrough for “fmtp” is indeed working but as the “imageattr” attribute is currently unsupported/not used/not passed through it is probably causing your resolution problem.

    Cheers,

  • What would need to be changed in the source code to accommodate this? Can the imageattr attribute be hard coded into h264_format_attr_sdp_generate()
    in res_format_attr_h264.c?