[Opalvoip-user] call to openphone_3.18_beta after registering to my FreeSwitch SIP Server -- openphone only receives one black video frame

[Evergreen H. <eve...@gm...>]

Hi, Robert,
  I am testing the `DoRegister` and `DoCall` functions of
`opal/samples/c_api/main.c`, and I come across this problem.
1. c_api.exe successfully registered to my FreeSwitch SIP Server with "
sip:1001@172.25.31.191"
2. openphone_3.18_beta successfully registered to the same FreeSwitch SIP
Server with "sip:1002@172.25.31.191"; (View -> Options -> SIP -> Add)
3. c_api.exe call to openphone with "sip:1002@172.25.31.191", call
established, here's the output of c_api.exe:
    > Media stream audio out eNoRole opened using G.711-uLaw-64k.
    > Media stream audio in eNoRole opened using G.711-uLaw-64k.
    > Media stream video out eNoRole opened using H.264-1.
    > Media stream video in eNoRole opened using H.264-1.
   and here's the output of openphone log window:
  > Started sending to sip, session 1, G.711-uLaw-64k, 20ms
  > Started sending to sip, session 2, H.264-1
  > Started receiving from sip, session 1, G.711-uLaw-64k
  > Started receiving from sip, session 2, H.264-1
  > Established call from sip:mod_sofia@121.40.170.194:5060 to
sip:1002@172.25.32.61:5060
4. problem: **openphone's video windows is black **, its local preview
windows is ok.

I check the wireshark captures:
1. c_api.exe has H264 video sent to FreeSwitch SIP server
2. FreeSwitch only send one black video frame to Openphone
3. Openphone displays the black video frame

however, if I use openphone instead of c_api.exe, it can register
successfully and make call to another openphone correctly(ok to display
video).

I carefully read the related code of openphone(register and call), and
compare it to c_api/main.c, I don't find any diffenrence currently.
the `main` function of c_api/main.c is like this:
```C
int main() {
    if (!InitialiseOPAL())
      return 1;
    const char *from = "sip:1001@172.25.31.191";
    const char *to = "sip:1002@172.25.31.191";
    const char *passwd = "1234";
    DoRegister(from, passwd);
    // sleep for seconds, make sure registration is done
   DoCall(from, to);
   while(1) {}
}
```
I make a breakpoint on `bool SIPEndPoint::Register(const
SIPRegister::Params & newParams, PString & aor, SIP_PDU::StatusCodes *
reason)`
and I observed that `SIPRegister::Params params` has same parameters as
openphone's:
```C
    params.m_addressOfRecord = "sip:1001@172.25.31.191";
    params.m_registrarAddress = "172.25.31.191";
    params.m_authID = "1001";
    params.m_password = "1234";
    params.m_expire = 300;
    params.m_compatibility = SIPRegister::e_FullyCompliant;
```

I don't know why FreeSwitch only transfer one black video frame to
openphone. Is there any problem with my `DoRegister` or `DoCall`?

Best Regards,
Alex