Hi all.
I just set up an asterisk server on my debian box.
After some fighting with asterisk’s config, I finally succeeded to make two android phones to call each other. Even video call is working ! So it’s pretty cool.
My configuration is really basic. I’m using imsDroid softphone on the android phones.
Now, I need to be able to do file transfer (file sharing) between those two phones.
imsDroid have this built-in capability. But when I try to send a file (in this case, an image), I get this error on asterisk:
WARNING[19405]: chan_sip.c:9084 process_sdp: Unsupported SDP media type in offer: message 34515 TCP/MSRP *
WARNING[19405]: chan_sip.c:9177 process_sdp: Failing due to no acceptable offer found
I’ve been searching all day on google and forums, I’ve read many papers but I can’t find anything to resolve this issue.
I bet I’m missing something.
Do I need to add a codec for this to work ? How can I debug this ?
Please consider that I’m a beginner with asterisk and with the SIP protocol.
Thanks in advance 
Have a great day !