rtspclient.cpp

c++实现的流媒体库,和mplayer结合就可以实现多媒体的网络播放,属于开源项目,很值得研究.

	// Also, tell the RDT source to use the RTSP TCP socket:
	RealRDTSource* rdtSource
	  = (RealRDTSource*)(subsession.readSource());
	rdtSource->setInputSocket(fInputSocketNum);
      }
    }
#endif

    char const *prefix, *separator, *suffix;
    constructSubsessionURL(subsession, prefix, separator, suffix);
    char* transportFmt;

    if (strcmp(subsession.protocolName(), "UDP") == 0) {
      char const* setupFmt = "SETUP %s%s RTSP/1.0\r\n";
      unsigned setupSize = strlen(setupFmt)
        + strlen(prefix) + strlen (separator);
      setupStr = new char[setupSize];
      sprintf(setupStr, setupFmt, prefix, separator);

      transportFmt = "Transport: RAW/RAW/UDP%s%s%s=%d-%d\r\n";
    } else {
      char const* setupFmt = "SETUP %s%s%s RTSP/1.0\r\n";
      unsigned setupSize = strlen(setupFmt)
        + strlen(prefix) + strlen (separator) + strlen(suffix);
      setupStr = new char[setupSize];
      sprintf(setupStr, setupFmt, prefix, separator, suffix);

      transportFmt = "Transport: RTP/AVP%s%s%s=%d-%d\r\n";
    }

    if (transportStr == NULL) {
      // Construct a "Transport:" header.
      char const* transportTypeStr;
      char const* modeStr = streamOutgoing ? ";mode=receive" : "";
          // Note: I think the above is nonstandard, but DSS wants it this way
      char const* portTypeStr;
      unsigned short rtpNumber, rtcpNumber;
      if (streamUsingTCP) { // streaming over the RTSP connection
	transportTypeStr = "/TCP;unicast";
	portTypeStr = ";interleaved";
	rtpNumber = fTCPStreamIdCount++;
	rtcpNumber = fTCPStreamIdCount++;
      } else { // normal RTP streaming      
	unsigned connectionAddress = subsession.connectionEndpointAddress();
	Boolean requestMulticastStreaming = IsMulticastAddress(connectionAddress)
	  || (connectionAddress == 0 && forceMulticastOnUnspecified);
	transportTypeStr = requestMulticastStreaming ? ";multicast" : ";unicast";
	portTypeStr = ";client_port";
	rtpNumber = subsession.clientPortNum();
	if (rtpNumber == 0) {
	  envir().setResultMsg("Client port number unknown\n");
	  break;
	}
	rtcpNumber = rtpNumber + 1;
      }

      unsigned transportSize = strlen(transportFmt)
	+ strlen(transportTypeStr) + strlen(modeStr) + strlen(portTypeStr) + 2*5 /* max port len */;
      transportStr = new char[transportSize];
      sprintf(transportStr, transportFmt,
	      transportTypeStr, modeStr, portTypeStr, rtpNumber, rtcpNumber);
    }

    // (Later implement more, as specified in the RTSP spec, sec D.1 #####)
    char* const cmdFmt =
      "%s"
      "CSeq: %d\r\n"
      "%s"
      "%s"
      "%s"
      "%s"
      "\r\n";

    unsigned cmdSize = strlen(cmdFmt)
      + strlen(setupStr)
      + 20 /* max int len */
      + strlen(transportStr)
      + strlen(sessionStr)
      + strlen(authenticatorStr)
      + fUserAgentHeaderStrSize;
    cmd = new char[cmdSize];
    sprintf(cmd, cmdFmt,
	    setupStr,
	    ++fCSeq,
	    transportStr,
	    sessionStr,
	    authenticatorStr,
	    fUserAgentHeaderStr);
    delete[] authenticatorStr;
    if (sessionStr[0] != '\0') delete[] sessionStr;
    delete[] setupStr; delete[] transportStr;

    // And then send it:
    if (!sendRequest(cmd, "SETUP")) break;

    // Get the response from the server:
    unsigned bytesRead; unsigned responseCode;
    char* firstLine; char* nextLineStart;
    if (!getResponse("SETUP", bytesRead, responseCode, firstLine, nextLineStart)) break;

    // Look for a "Session:" header (to set our session id), and
    // a "Transport: " header (to set the server address/port)
    // For now, ignore other headers.
    char* lineStart;
    char* sessionId = new char[fResponseBufferSize]; // ensures we have enough space
    unsigned cLength = 0;
    while (1) {
      lineStart = nextLineStart;
      if (lineStart == NULL) break;

      nextLineStart = getLine(lineStart);

      if (sscanf(lineStart, "Session: %[^;]", sessionId) == 1) {
	subsession.sessionId = strDup(sessionId);
	delete[] fLastSessionId; fLastSessionId = strDup(sessionId);

	// Also look for an optional "; timeout = " parameter following this:
	char* afterSessionId
	  = lineStart + strlen(sessionId) + strlen ("Session: ");;
	int timeoutVal;
	if (sscanf(afterSessionId, "; timeout = %d", &timeoutVal) == 1) {
	  fSessionTimeoutParameter = timeoutVal;
	}
	continue;
      }

      char* serverAddressStr;
      portNumBits serverPortNum;
      unsigned char rtpChannelId, rtcpChannelId;
      if (parseTransportResponse(lineStart,
				 serverAddressStr, serverPortNum,
				 rtpChannelId, rtcpChannelId)) {
	delete[] subsession.connectionEndpointName();
	subsession.connectionEndpointName() = serverAddressStr;
	subsession.serverPortNum = serverPortNum;
	subsession.rtpChannelId = rtpChannelId;
	subsession.rtcpChannelId = rtcpChannelId;
	continue;
      }

      // Also check for a "Content-Length:" header.  Some weird servers include this
      // in the RTSP "SETUP" response.
      if (sscanf(lineStart, "Content-Length: %d", &cLength) == 1) continue;
    } 
    delete[] sessionId;

    if (subsession.sessionId == NULL) {
      envir().setResultMsg("\"Session:\" header is missing in the response");
      break;
    }

    // If we saw a "Content-Length:" header in the response, then discard whatever
    // included data it refers to:
    if (cLength > 0) {
      char* dummyBuf = new char[cLength];
      getResponse1(dummyBuf, cLength);
      delete[] dummyBuf;
    }

    if (streamUsingTCP) {
      // Tell the subsession to receive RTP (and send/receive RTCP)
      // over the RTSP stream:
      if (subsession.rtpSource() != NULL)
	subsession.rtpSource()->setStreamSocket(fInputSocketNum,
						subsession.rtpChannelId);
      if (subsession.rtcpInstance() != NULL)
	subsession.rtcpInstance()->setStreamSocket(fInputSocketNum,
						   subsession.rtcpChannelId);
    } else {
      // Normal case.
      // Set the RTP and RTCP sockets' destination address and port
      // from the information in the SETUP response (if present): 
      netAddressBits destAddress = subsession.connectionEndpointAddress();
      if (destAddress == 0) destAddress = fServerAddress;
      subsession.setDestinations(destAddress);
    }

    delete[] cmd;
    return True;
  } while (0);

  delete[] cmd;
  return False;
}

static char* createScaleString(float scale, float currentScale) {
  char buf[100];
  if (scale == 1.0f && currentScale == 1.0f) {
    // This is the default value; we don't need a "Scale:" header:
    buf[0] = '\0';
  } else {
    Locale("C", LC_NUMERIC);
    sprintf(buf, "Scale: %f\r\n", scale);
  }

  return strDup(buf);
}
      
static char* createRangeString(float start, float end) {
  char buf[100];
  if (start < 0) {
    // We're resuming from a PAUSE; there's no "Range:" header at all
    buf[0] = '\0';
  } else if (end < 0) {
    // There's no end time:
    Locale("C", LC_NUMERIC);
    sprintf(buf, "Range: npt=%.3f-\r\n", start);
  } else {
    // There's both a start and an end time; include them both in the "Range:" hdr
    Locale("C", LC_NUMERIC);
    sprintf(buf, "Range: npt=%.3f-%.3f\r\n", start, end);
  }

  return strDup(buf);
}
      
static char const* NoSessionErr = "No RTSP session is currently in progress\n";

Boolean RTSPClient::playMediaSession(MediaSession& session,
				     float start, float end, float scale) {
#ifdef SUPPORT_REAL_RTSP
  if (session.isRealNetworksRDT) {
    // This is a RealNetworks stream; set the "Subscribe" parameter before proceeding:
    char* streamRuleString = RealGetSubscribeRuleString(&session);
    setMediaSessionParameter(session, "Subscribe", streamRuleString);
    delete[] streamRuleString;
  }
#endif
  char* cmd = NULL;
  do {
    // First, make sure that we have a RTSP session in progress
    if (fLastSessionId == NULL) {
      envir().setResultMsg(NoSessionErr);
      break;
    }

    // Send the PLAY command:

    // First, construct an authenticator string:
    char* authenticatorStr
      = createAuthenticatorString(&fCurrentAuthenticator, "PLAY", fBaseURL);
    // And then a "Scale:" string:
    char* scaleStr = createScaleString(scale, session.scale());
    // And then a "Range:" string:
    char* rangeStr = createRangeString(start, end);

    char* const cmdFmt =
      "PLAY %s RTSP/1.0\r\n"
      "CSeq: %d\r\n"
      "Session: %s\r\n"
      "%s"
      "%s"
      "%s"
      "%s"
      "\r\n";

    char const* sessURL = sessionURL(session);
    unsigned cmdSize = strlen(cmdFmt)
      + strlen(sessURL)
      + 20 /* max int len */
      + strlen(fLastSessionId)
      + strlen(scaleStr)
      + strlen(rangeStr)
      + strlen(authenticatorStr)
      + fUserAgentHeaderStrSize;
    cmd = new char[cmdSize];
    sprintf(cmd, cmdFmt,
	    sessURL,
	    ++fCSeq,
	    fLastSessionId,
	    scaleStr,
	    rangeStr,
	    authenticatorStr,
	    fUserAgentHeaderStr);
    delete[] scaleStr;
    delete[] rangeStr;
    delete[] authenticatorStr;

    if (!sendRequest(cmd, "PLAY")) break;

    // Get the response from the server:
    unsigned bytesRead; unsigned responseCode;
    char* firstLine; char* nextLineStart;
    if (!getResponse("PLAY", bytesRead, responseCode, firstLine, nextLineStart)) break;

    // Look for various headers that we understand:
    char* lineStart;
    while (1) {
      lineStart = nextLineStart;
      if (lineStart == NULL) break;

      nextLineStart = getLine(lineStart);

      if (parseScaleHeader(lineStart, session.scale())) continue;
      if (parseRangeHeader(lineStart, session.playStartTime(), session.playEndTime())) continue;

      u_int16_t seqNum; u_int32_t timestamp;
      if (parseRTPInfoHeader(lineStart, seqNum, timestamp)) {
	// This is data for our first subsession.  Fill it in, and do the same for our other subsessions:
	MediaSubsessionIterator iter(session);
	MediaSubsession* subsession;
	while ((subsession = iter.next()) != NULL) {
	  subsession->rtpInfo.seqNum = seqNum;
	  subsession->rtpInfo.timestamp = timestamp;
	  subsession->rtpInfo.infoIsNew = True;

	  if (!parseRTPInfoHeader(lineStart, seqNum, timestamp)) break;
	}
	continue;
      }
    }

    if (fTCPStreamIdCount == 0) { // we're not receiving RTP-over-TCP
      // Arrange to handle incoming requests sent by the server
      envir().taskScheduler().turnOnBackgroundReadHandling(fInputSocketNum,
	   (TaskScheduler::BackgroundHandlerProc*)&incomingRequestHandler, this);
    }

    delete[] cmd;
    return True;
  } while (0);

  delete[] cmd;
  return False;
}

Boolean RTSPClient::playMediaSubsession(MediaSubsession& subsession,
					float start, float end, float scale,
					Boolean hackForDSS) {
  char* cmd = NULL;
  do {
    // First, make sure that we have a RTSP session in progress
    if (subsession.sessionId == NULL) {
      envir().setResultMsg(NoSessionErr);
      break;
    }

    // Send the PLAY command:

    // First, construct an authenticator string:
    char* authenticatorStr
      = createAuthenticatorString(&fCurrentAuthenticator, "PLAY", fBaseURL);
    // And then a "Scale:" string:
    char* scaleStr = createScaleString(scale, subsession.scale());
    // And then a "Range:" string:
    char* rangeStr = createRangeString(start, end);

    char* const cmdFmt =
      "PLAY %s%s%s RTSP/1.0\r\n"
      "CSeq: %d\r\n"
      "Session: %s\r\n"
      "%s"
      "%s"
      "%s"
      "%s"
      "\r\n";

    char const *prefix, *separator, *suffix;
    constructSubsessionURL(subsession, prefix, separator, suffix);
    if (hackForDSS || fServerIsKasenna) {
      // When "PLAY" is used to inject RTP packets into a DSS
      // (violating the RTSP spec, btw; "RECORD" should have been used)
      // the DSS can crash (or hang) if the '/trackid=...' portion of
      // the URL is present.
      separator = suffix = "";
    }

    unsigned cmdSize = strlen(cmdFmt)
      + strlen(prefix) + strlen(separator) + strlen(suffix)
      + 20 /* max int len */
      + strlen(subsession.sessionId)
      + strlen(scaleStr)
      + strlen(rangeStr)
      + strlen(authenticatorStr)
      + fUserAgentHeaderStrSize;
    cmd = new char[cmdSize];
    sprintf(cmd, cmdFmt,
	    prefix, separator, suffix,
	    ++fCSeq,
	    subsession.sessionId,
	    scaleStr,
	    rangeStr,
	    authenticatorStr,
	    fUserAgentHeaderStr);
    delete[] scaleStr;
    delete[] rangeStr;
    delete[] authenticatorStr;

    if (!sendRequest(cmd, "PLAY")) break;

    // Get the response from the server:
    unsigned bytesRead; unsigned responseCode;
    char* firstLine; char* nextLineStart;
    if (!getResponse("PLAY", bytesRead, responseCode, firstLine, nextLineStart)) break;

    // Look for various headers that we understand:
    char* lineStart;
    while (1) {
      lineStart = nextLineStart;
      if (lineStart == NULL) break;

      nextLineStart = getLine(lineStart);

      if (parseScaleHeader(lineStart, subsession.scale())) continue;
      if (parseRangeHeader(lineStart, subsession._playStartTime(), subsession._playEndTime())) continue;

      u_int16_t seqNum; u_int32_t timestamp;
      if (parseRTPInfoHeader(lineStart, seqNum, timestamp)) {
	subsession.rtpInfo.seqNum = seqNum;
	subsession.rtpInfo.timestamp = timestamp;
	subsession.rtpInfo.infoIsNew = True;
	continue;
      }
    }