Hi to everybody, I've got a couple hopefully basic questions about live streaming with live555.
I'd like to stream h263-encoded videos to various media players (mainly realplayer on mobile phones). What I do now is starting a thread that captures live frames and encodes them in H263 with ffmpeg. The thread writes on a Unix named pipe (FIFO). Then I create a RTSPServer instance, create a ServerMediaSession and add a subsession, passing the FIFO file name as the subsession parameter. A few problems arise, in order of importance: 1) VLC and Mplayer are able to play the live video, while RealPlayer isn't. I captured the network conversation with wireshark, and it seems the RTSP negotiation is done correctly, but the server just won't send RTP packets (while with VLC or MPlayer it does). Here's the captured RTSP conversation: User-Agent: RealMedia Player/mc.28.16.01 (s60; epoc_av21_thumb) CSeq: 1 RTSP/1.0 200 OK CSeq: 1 Date: Mon, Dec 17 2007 11:26:51 GMT Public: OPTIONS, DESCRIBE, SETUP, TEARDOWN, PLAY, PAUSE DESCRIBE rtsp://217.133.231.30/H263ESVideoTest RTSP/1.0 x-wap-profile: "http://nds1.nds.nokia.com/uaprof/NN70-1r100.xml"; ClientID: RealOnePlayer_s60.28.16.01_21-Apr-2006_10:28:59_epoc_av21_thumb Accept: application/sdp Bandwidth: 298368 GUID: 00000000-0000-0000-0000-000000000000 User-Agent: RealMedia Player/mc.28.16.01 (s60; epoc_av21_thumb) CSeq: 2 RTSP/1.0 200 OK CSeq: 2 Date: Mon, Dec 17 2007 11:26:51 GMT Content-Base: rtsp://217.133.231.30/H263ESVideoTest/ Content-Type: application/sdp Content-Length: 384 v=0 o=- 1197890794075912 1 IN IP4 217.133.231.30 s=Session streamed live by "rtspServer" i=H263ESVideoTest t=0 0 a=tool:LIVE555 Streaming Media v2007.12.06 a=type:broadcast a=control:* a=range:npt=0- a=x-qt-text-nam:Session streamed live by "rtspServer" a=x-qt-text-inf:H263ESVideoTest m=video 0 RTP/AVP 96 c=IN IP4 0.0.0.0 a=rtpmap:96 H263-1998/90000 a=control:track1 SETUP rtsp://217.133.231.30/H263ESVideoTest/track1 RTSP/1.0 x-wap-profile: "http://nds1.nds.nokia.com/uaprof/NN70-1r100.xml"; Transport: RTP/AVP;unicast;client_port=26022-26023;mode=play User-Agent: RealMedia Player/mc.28.16.01 (s60; epoc_av21_thumb) CSeq: 3 RTSP/1.0 200 OK CSeq: 3 Date: Mon, Dec 17 2007 11:26:52 GMT Transport: RTP/AVP;unicast;destination=217.201.153.216;source=217.133.231.30;client_port=26022-26023;server_port=6970-6971 Session: 1 PLAY rtsp://217.133.231.30/H263ESVideoTest/ RTSP/1.0 Range: npt=0.000- Session: 1 User-Agent: RealMedia Player/mc.28.16.01 (s60; epoc_av21_thumb) CSeq: 4 RTSP/1.0 200 OK CSeq: 4 Date: Mon, Dec 17 2007 11:26:52 GMT Range: npt=0.000- Session: 1 RTP-Info: url=rtsp://217.133.231.30/H263ESVideoTest/track1;seq=1723;rtptime=1928192185 (The client was RealPlayer from a Nokia N70 mobile, same behaviour with RealPlayer for Linux on the same host of the server, so it's not a network problem). The client will then send RTCP control packets regularly, along with some strange RTP packets with payload = 73, but the server won't send any RTP or RTCP packet, even if the PLAY command was accepted by the server. 2) VLC and Mplayer correctly view the live video, but they often will play a chunk of it, then "freeze" the frame for a few seconds, then play another chunk, then freeze again. What could the problem be? Buffering? Too many packets? (I acquire at 25 fps, but vlc is on the same host as the server). Please note all this problems disappear when i stream from a file containing raw h263 data @ 25 fps. 3) In my naive implementation, I start the encoder thread after adding the subsession and before the taskScheduler().doEventLoop() call. I'd like, instead, to start my decoder thread when and only when a client does a request for the stream (sparing resources when the server is idle), in an "on demand" fashion. How can I do that? I thought about starting the decoder thread in specialClientAccessCheck method, subclassing RTSPServer class, but I don't think it's the right way to do it (after all, specialClientAccessCheck is for checking IPs and request URLs). Best regards and thanks in advance for your help, Cristiano. -- Belloni Cristiano _______________________________________________ live-devel mailing list live-devel@lists.live555.com http://lists.live555.com/mailman/listinfo/live-devel
