[Live-devel] [Mirasys] Live555 RTSP server questions

[Victor Vitkovskiy]

Hello Ross, 

Thank you for your answers. 

Still I have some opened questions:
>> You don’t need to be concerned at all with the internals of the LIVE555 code to do what you want here.
This doesn't give me any information how to do this :).
If I don't need to subclass from RTSPServer then how I can detect new client connected / disconnected and what server session is used by this client (as we can have several sessions in RTSPServer)?

>> Yes you can.  This FAQ entry http://live555.com/liveMedia/faq.html#liveInput-unicast
>> tells you exactly what you need to do.  Unless your source data is accessible as a file (in your OS’s file system), then you will need to write a subclass of “FramedSource” that delivers, on demand, a frame of encoded data each time “doGetNextFrame()” is called.  See the “DeviceSource.cpp” code for a model of how to do this.
It is clear for me how to create my H264FramedSource, but it is not clear how to use it in higher levels. 
testOnDemandRTSPServer example use this code: 
        ServerMediaSession* sms = ServerMediaSession::createNew(*env, streamName, streamName, descriptionString);
        sms->addSubsession(H264VideoFileServerMediaSubsession::createNew(*env, inputFileName, reuseFirstSource));
        rtspServer->addServerMediaSession(sms);
So I need to subclass from H264VideoFileServerMediaSubsession and override those two virtual functions: createNewStreamSource and createNewRTPSink, is this correct? 
Or I need to subclass from OnDemandServerMediaSubsession and do the same thing (like reading SDP information from H.264 stream)?

Best regards,
-----------------------------------------
Victor Vitkovskiy
Senior software developer
mailto: victor.vitkovskiy at mirasys.com
www.mirasys.com


-----Original Message-----
From: live-devel <live-devel-bounces at us.live555.com> On Behalf Of Ross Finlayson
Sent: Wednesday, 12 January 2022 11:02
To: LIVE555 Streaming Media - development & use <live-devel at us.live555.com>
Subject: Re: [Live-devel] [Mirasys] Live555 RTSP server questions

EXTERNAL


> On Jan 12, 2022, at 9:41 PM, Victor Vitkovskiy <victor.vitkovskiy at mirasys.com> wrote:
>
> Dear Support,
>
> My name is Victor, I am investigating possibility to use Live555 in Mirasys VMS system and I have several questions, could you please help me?
>
>       • We need to create RTSP server that will stream data from our system if client connects to it.
> Unfortunately, I have not found any callbacks / events related to client connection in RTSPServer class.

You don’t need to be concerned at all with the internals of the LIVE555 code to do what you want here.


>       • There are a lot of examples how to stream files from PC, but I haven’t found any example how I can stream continuously data from memory.
> E.g. I get some video stream from IP camera, process it and then I want to stream this over RTSP.
> I have found this description how to do this:
>                 But what about the "testOnDemandRTSPServer" test program (for streaming via unicast)? How can I modify it so that it takes input from a live source instead of from a file?
>                 But still I can’t cope with this

Yes you can.  This FAQ entry
        http://live555.com/liveMedia/faq.html#liveInput-unicast
tells you exactly what you need to do.  Unless your source data is accessible as a file (in your OS’s file system), then you will need to write a subclass of “FramedSource” that delivers, on demand, a frame of encoded data each time “doGetNextFrame()” is called.  See the “DeviceSource.cpp” code for a model of how to do this.

But basically, the “testOnDemandRTSPServer” code (and an appropriate “ServerMediaSubsession” subclass) would be the appropriate model for you to use here.

Again, you don’t need to concern yourselves with the internals of the LIVE555 code.  That’s my job, not yours :-)


>       • Is there any example how to stream some xml metadata? What media source I should use to stream it over RTSP?

I can answer this question, but not until you’ve demonstrated that you’ve gotten more common media streaming (e.g., H.264 video) to work.  You need to show that you can walk before you try to run :-)


>       • If I understood correctly, it should be possible to add several media sources to RTSP session, e.g. if IP camera has 2 video streams (one is with full resolution and one is with cropped one) can I add those streams to one RTSP session as different tracks?

You would do this by adding two different “ServerMediaSession” objects - each with a different name - to your RTSP server.  One “ServerMediaSession” would be for the high-resolution stream; the other would be for the low-resolution stream.  A RTSP client would use the stream name (i.e., in the “rtsp://“ URL) to select which stream it wanted.

(This is basically what the “testOnDemandRTSPServer” code does - except that it uses different “ServerMediaSession” objects for streaming different codec types - not different resolutions of the same codec type.)


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/


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