[Live-devel] Buffering an H264 Video Stream

[Mark Bondurant]

Sorry. That wasn't clear. Yes, FramedSource derives from MediaSource, which derives from Medium. RTSPClient derives from Medium.

In the example program you have the ourRTSPClient with a StreamClientState object attached. You "strobe" the session object to cause the client to pump frames through. I suppose in my case, I would have a session a camera.

In testH264VideoToTransportStream you have a FramedSource file input, ByteStreamFileSource, which you  pass in to H264VideoStreamFramer as an argument within the context of a session object.

Looking at these two pieces together, I see what I need, but I also see two disparate paradigms. The framer wants a FramedSource and RTSPClient presents a Media source. RTSPClient understands RTSP, the framer understands H264. But they don't fit together in any way I can see. I see a Framed paradigm and a Media paradigm.

From: live-devel [mailto:live-devel-bounces at ns.live555.com] On Behalf Of Ross Finlayson
Sent: Monday, November 03, 2014 1:38 PM
To: LIVE555 Streaming Media - development & use
Subject: Re: [Live-devel] Buffering an H264 Video Stream

I need to keep a constant 3 second buffer of an H264 video stream. It's for security cameras. When something trips the camera, I replay the 3 seconds and then 6 more to see the event (One hopes I'll catch some ghosts or mountain lions, but really it's to catch car thieves!).  With mpeg it was easy because mpeg has discrete frames, but the much better definition h264 doesn't. I mean it does, but they're spread out over an indefinite series of NAL packets that can contain various varieties of slices. Squishing together into a discrete frame is a problem.


 It seems to me that there are two different paradigms at work in live555. Modules that derive from Medium and modules that derive from MediaSource.

No, this is completely wrong.  (Note that “MediaSource” is a subclass of “Medium”.)

I suggest that you begin by reviewing the “testRTSPClient” demo application (in the “testProgs” directory).  Note, in particular, the “DummySink” object that receives ‘frames’ (for H.264 video, each ‘frame’ will actually be a NAL unit).  Note the code for “DummyRTPSink::afterGettingFrame()” ("testRTSPClient.cpp”, lines 500-521).  For your own RTSP client application, you could write your own ‘sink’ class (a subclass of “MediaSink”) that receives H.264 NAL units, and processes them however you want.

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

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