Looking for a SIP client that can use an h.264 RTSP stream as a video source - sip

Question

We are looking to integrate an IP camera (h.264 RTSP stream) with an asterisk PBX system for use in a school for distributed education (so a remote teacher can "dial in and teach").
Ideally we would like to be able to create a SIP client as an autoanswer pbx extension.
We are considering running a *nix box that can use a network video stream as a source for video, mix a separate audio source and present a SIP endpoint.
I understand that SIP express router may be able to:
"call an external C script, which could parse and change the SDP info within the SIP headers of clients it porxy's with, and change address of where it expects to recieve media from."
but I'm thinking it may be easier to look for a way to present an h.264 rtsp stream as /dev/videoX and use a standard SIP client.
If anyone has any pointers or any ideas for research I'd be really appreciative :-)
Thanks for reading!
W
p.s. there are IP cameras out there that claim to have SIP clients, but all I have seen only offer SIP for establishing a bi-directional audio session.

Answer 1

I don't know whether you found the correct answer to this question or not after all this time, but maybe I can give you some advice with VoIP and IP camera management and it would help anybody who has the same problem.
Your goal (if I understand your problem correctly) is basically creating a conference call solution which answers all the incoming calls and attach the IP camera video to all of these calls. I currently work at a company called Ozeki and - I don't know if there's an open-source solution for your problem or not - I'm going to show you an example code with SIP account registration, IP camera connection and answer all the incoming calls with the camera video.
So here is the source code:
public partial class Form1 : Form
{
private IIPCamera _camera;
private DrawingImageProvider _imageProvider;
private MediaConnector _connector;
private VideoViewerWF _videoViewerWf;
private ISoftPhone _softphone;
private IPhoneLine _phoneLine;
private IPhoneCall _call;
private PhoneCallAudioSender _audioSender;
private PhoneCallVideoSender _videoSender;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
_softphone = SoftPhoneFactory.CreateSoftPhone(5000, 10000);
_softphone.IncomingCall += softphone_IncomingCall;
_connector = new MediaConnector();
_videoSender = new PhoneCallVideoSender();
_audioSender = new PhoneCallAudioSender();
_imageProvider = new DrawingImageProvider();
_videoViewerWf = new VideoViewerWF();
SetVideoViewer();
}
private void SetVideoViewer()
{
CameraBox.Controls.Add(_videoViewerWf);
_videoViewerWf.Size = new Size(260, 180);
_videoViewerWf.BackColor = Color.Black;
_videoViewerWf.TabStop = false;
_videoViewerWf.FlipMode = FlipMode.None;
_videoViewerWf.Location = new Point(35, 30);
_videoViewerWf.Name = "_videoViewerWf";
}
private void Register(bool registrationRequired, string displayName, string userName, string authenticationId, string registerPassword, string domainHost)
{
try
{
var account = new SIPAccount(registrationRequired, displayName, userName, authenticationId, registerPassword, domainHost);
_phoneLine = _softphone.CreatePhoneLine(account);
_phoneLine.RegistrationStateChanged += phoneLine_RegistrationStateChanged;
_softphone.RegisterPhoneLine(_phoneLine);
}
catch (Exception ex)
{
label_Phoneline.Text = ex.Message;
}
}
private void phoneLine_RegistrationStateChanged(object sender, RegistrationStateChangedArgs e)
{
InvokeGuiThread(() => label_Phoneline.Text = e.State.ToString());
}
private void softphone_IncomingCall(object sender, VoIPEventArgs<iphonecall> e)
{
if (_camera != null)
{
_call = e.Item;
_call.CallStateChanged += call_CallStateChanged;
ConnectToCall();
_call.Answer();
}
}
private void ConnectToCall()
{
_videoSender.AttachToCall(_call);
_audioSender.AttachToCall(_call);
_connector.Connect(_camera.VideoChannel, _videoSender);
_connector.Connect(_camera.AudioChannel, _audioSender);
}
private void call_CallStateChanged(object sender, CallStateChangedArgs e)
{
InvokeGuiThread(() => label_Call.Text = e.State.ToString());
if (e.State == CallState.Completed)
if (_call != null)
{
_call.CallStateChanged -= call_CallStateChanged;
_connector.Disconnect(_camera.VideoChannel, _videoSender);
_connector.Disconnect(_camera.AudioChannel, _audioSender);
}
}
private void button_Connect_Click(object sender, EventArgs e)
{
_camera = IPCameraFactory.GetCamera("cameraIPAddress:8080", "admin", "admin");
_connector.Connect(_camera.VideoChannel, _imageProvider);
_videoViewerWf.SetImageProvider(_imageProvider);
_videoViewerWf.Start();
_camera.Start();
}
private void button_SIPRegister_Click(object sender, EventArgs e)
{
Register(true, "100", "100", "100", "100", "PBXAddress");
}
private void InvokeGuiThread(Action action)
{
BeginInvoke(action);
}
}
And the (example) GUI:
If you click on Connect button then the IPCameraFactory.GetCamera() will be called which is for connecting to the specified camera using the arguments (RTSP/RTP/HTTP messages in the background).
The Register button calls the Register() method to register your SIP account to the PBX. You can check the registration status at the Status label.
If there is an incoming call then the answer will occur automatically and the camera video and audio channel will attach to the call. So the caller will see and hear you.
Note:
Most of the IP camera microphones have really bad quality so you may connect your own microphone to the call. It's really simple too.
Create a Microphone object:
Microphone microphone = Microphone.GetDefaultDevice();
if (microphone != null)
microphone.Start();
And if there's an incoming call then connect this microphone to the call:
_connector.Connect(microphone, _audioSender);
And that's it. I hope I could help you!

Answer 2

live555 has some open-source implementations like openRTSP and playSIP which could help with your requirements.