[Live-devel] proxyServer: Extra bytes before PLAY response

[Abins Joseph Jose]

Hi,

I have noticed that when a client connects to the live555ProxyServer  using RTP over TCP, some extra bytes are present before the PLAY response. This happens only if the client is not the first one to connect to the live555ProxyServer (ie. There are existing clients that have connected too). This behavior doesn’t happen in case of RTP over UDP.

I suspect the reason is because in the RTSPServer.cpp file, in response to the PLAY command,  the startStream for each media subsession is called and then the PLAY response is sent. I think that the startStream may be sending the data before the PLAY response, but I am not able to track down the exact place where this is happening.

Below is the wireshark trace captured between the openRTSP and live555ProxyServer with this issue:

OPTIONS rtsp://172.22.65.58/proxyStream RTSP/1.0
CSeq: 2
User-Agent: openRTSP.exe (LIVE555 Streaming Media v2014.02.26)

RTSP/1.0 200 OK
CSeq: 2
Date: Wed, Mar 12 2014 09:10:19 GMT
Public: OPTIONS, DESCRIBE, SETUP, TEARDOWN, PLAY, PAUSE, GET_PARAMETER, SET_PARAMETER

DESCRIBE rtsp://172.22.65.58/proxyStream RTSP/1.0
CSeq: 3
User-Agent: openRTSP.exe (LIVE555 Streaming Media v2014.02.26)
Accept: application/sdp

RTSP/1.0 200 OK
CSeq: 3
Date: Wed, Mar 12 2014 09:10:19 GMT
Content-Base: rtsp://172.22.65.58/proxyStream/
Content-Type: application/sdp
Content-Length: 536

v=0
o=- 1394615373237045 1 IN IP4 172.22.65.58
s=LIVE555 Streaming Media v2014.02.26
i=LIVE555 Streaming Media v2014.02.26
t=0 0
a=tool:LIVE555 Streaming Media v2014.02.26
a=type:broadcast
a=control:*
a=range:npt=0-
a=x-qt-text-nam:LIVE555 Streaming Media v2014.02.26
a=x-qt-text-inf:LIVE555 Streaming Media v2014.02.26
m=video 0 RTP/AVP 96
c=IN IP4 0.0.0.0
b=AS:50000
a=rtpmap:96 H264/90000
a=fmtp:96 packetization-mode=1;profile-level-id=420029;sprop-parameter-sets=Z0IAKeKQFAe2AtwEBAaQeJEV,aM48gA==
a=control:track1

SETUP rtsp://172.22.65.58/proxyStream/track1 RTSP/1.0
CSeq: 4
User-Agent: openRTSP.exe (LIVE555 Streaming Media v2014.02.26)
Transport: RTP/AVP/TCP;unicast;interleaved=0-1

RTSP/1.0 200 OK
CSeq: 4
Date: Wed, Mar 12 2014 09:10:19 GMT
Transport: RTP/AVP/TCP;unicast;destination=172.22.65.73;source=172.22.65.58;interleaved=0-1
Session: 8A527274;timeout=65

PLAY rtsp://172.22.65.58/proxyStream/ RTSP/1.0
CSeq: 5
User-Agent: openRTSP.exe (LIVE555 Streaming Media v2014.02.26)
Session: 8A527274
Range: npt=0.000-

$..4......;......1.!.y.......+........;..
A2ML20710L....RTSP/1.0 200 OK
CSeq: 5
Date: Wed, Mar 12 2014 09:10:19 GMT
Range: npt=0.000-
Session: 8A527274
RTP-Info: url=rtsp://172.22.65.58/proxyStream/track1;seq=49180;rtptime=4135167983

Best regards,
Abins

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