Voici les ligne que je pense intéressantes dans le débug:

Authorization: Digest username="110",realm="asterisk",nonce="379df099",u ri="sip:100@172.16.10.49",response="9893b01261b280 cb81ed41698eaa5cf5",algorithm=MD5
Content-Length: 204

v=0
o=- 6 3 IN IP4 172.16.70.198
s=CounterPath eyeBeam 1.5
c=IN IP4 0.0.0.0
t=0 0
m=audio 19228 RTP/AVP 0 8 101
a=fmtp:101 0-15
a=rtpmap:101 telephone-event/8000
a=sendonly
m=video 0 RTP/AVP 34

<------------->
--- (13 headers 10 lines) ---
Sending to 172.16.70.198 : 24316 (no NAT)
Found RTP audio format 0
Found RTP audio format 8
Found RTP audio format 101
Found audio description format telephone-event for ID 101
Found RTP video format 34
Capabilities: us - 0x8000e (gsm|ulaw|alaw|h263), peer - audio=0xc (ulaw|alaw)/video=0x80000 (h263)/text=0x0 (nothing), combined - 0x8000c (ulaw|alaw|h263)
Non-codec capabilities (dtmf): us - 0x1 (telephone-event), peer - 0x1 (telephone-event), combined - 0x1 (telephone-event)
Peer audio RTP is at port 0.0.0.0:19228

Dans Eyebeam, dans Advanced/video codecs, dans la colone de droite "enable video" j'ai uniquement H.263.

Merci