Problem withvideo with Linphone softphone (h.264)

Dear Sirs

I have two Linphone registered in a PBX asterisk (all in the same LAN).

I am interested in make a video call with h264 codec, MP4V (in Linphone).

My problem is, only audio call is established, the video session does not start and video windows are closed when the call is established

I make a wireshark trace and Linphone A send to Asterisk in SIP(Invite)/SDP MP4V codec and asterisk change it to h.264 codec so Linphone B receive h.264 instead the MP4V and the video session is not open.

Can anyone tell me how to solve the problem?

With kinds regards

João Pereira Rosa