mediasession.cpp

流媒体传输协议的实现代码,非常有用.可以支持rtsp mms等流媒体传输协议

	fReadSource = fRTPSource
	  = QuickTimeGenericRTPSource::createNew(env(), fRTPSocket,
						 fRTPPayloadFormat,
						 fRTPTimestampFrequency,
						 mimeType);
	delete[] mimeType;
      } else if (strcmp(fCodecName, "X-MCT-TEXT") == 0) {
	// A UDP-packetized text stream (*not* a RTP stream)
	fReadSource = BasicUDPSource::createNew(env(), fRTPSocket);
	fRTPSource = NULL; // Note!
#ifdef SUPPORT_REAL_RTSP
      } else if (strcmp(fCodecName, "X-PN-REALAUDIO") == 0 ||
		 strcmp(fCodecName, "X-PN-MULTIRATE-REALAUDIO-LIVE") == 0 ||
		 strcmp(fCodecName, "X-PN-REALVIDEO") == 0 ||
		 strcmp(fCodecName, "X-PN-MULTIRATE-REALVIDEO-LIVE") == 0) {
	// A RealNetworks 'RDT' stream (*not* a RTP stream)
	fReadSource = RealRDTSource::createNew(env());
	fRTPSource = NULL; // Note!
	parentSession().isRealNetworksRDT = True;
#endif
      } else if (  strcmp(fCodecName, "PCMU") == 0 // PCM u-law audio
		   || strcmp(fCodecName, "GSM") == 0 // GSM audio
		   || strcmp(fCodecName, "PCMA") == 0 // PCM a-law audio
		   || strcmp(fCodecName, "L16") == 0 // 16-bit linear audio
		   || strcmp(fCodecName, "MP1S") == 0 // MPEG-1 System Stream
		   || strcmp(fCodecName, "MP2P") == 0 // MPEG-2 Program Stream
		   || strcmp(fCodecName, "L8") == 0 // 8-bit linear audio
		   || strcmp(fCodecName, "SPEEX") == 0 // SPEEX audio
		   ) {
	createSimpleRTPSource = True;
	useSpecialRTPoffset = 0;
      } else if (useSpecialRTPoffset >= 0) {
	// We don't know this RTP payload format, but try to receive
	// it using a 'SimpleRTPSource' with the specified header offset:
	createSimpleRTPSource = True;
      } else {
	env().setResultMsg("RTP payload format unknown or not supported");
	break;
      }
      
      if (createSimpleRTPSource) {
	char* mimeType
	  = new char[strlen(mediumName()) + strlen(codecName()) + 2] ;
	sprintf(mimeType, "%s/%s", mediumName(), codecName());
	fReadSource = fRTPSource
	  = SimpleRTPSource::createNew(env(), fRTPSocket, fRTPPayloadFormat,
				       fRTPTimestampFrequency, mimeType,
				       (unsigned)useSpecialRTPoffset,
				       doNormalMBitRule);
	delete[] mimeType;
      }
    }

    if (fReadSource == NULL) {
      env().setResultMsg("Failed to create read source");
      break;
    }
    
    // Finally, create our RTCP instance. (It starts running automatically)
    if (fRTPSource != NULL) {
      unsigned totSessionBandwidth = 500; // HACK - later get from SDP#####
      fRTCPInstance = RTCPInstance::createNew(env(), fRTCPSocket,
					      totSessionBandwidth,
					      (unsigned char const*)
					      fParent.CNAME(),
					      NULL /* we're a client */,
					      fRTPSource);
      if (fRTCPInstance == NULL) {
	env().setResultMsg("Failed to create RTCP instance");
	break;
      }
    }

    return True;
  } while (0);

  delete fRTPSocket; fRTPSocket = NULL;
  delete fRTCPSocket; fRTCPSocket = NULL;
  Medium::close(fRTCPInstance); fRTCPInstance = NULL;
  Medium::close(fReadSource); fReadSource = fRTPSource = NULL;
  fClientPortNum = 0;
  return False;
}

void MediaSubsession::deInitiate() {
  Medium::close(fRTCPInstance);
  fRTCPInstance = NULL;

  Medium::close(fReadSource); // this is assumed to also close fRTPSource
  fReadSource = NULL; fRTPSource = NULL;

  delete fRTCPSocket; delete fRTPSocket;
  fRTCPSocket = fRTPSocket = NULL;
}

Boolean MediaSubsession::setClientPortNum(unsigned short portNum) {
  if (fReadSource != NULL) {
    env().setResultMsg("A read source has already been created");
    return False;
  }

  fClientPortNum = portNum;
  return True;
}

unsigned MediaSubsession::connectionEndpointAddress() const {
  do {
    // Get the endpoint name from with us, or our parent session:
    char const* endpointString = connectionEndpointName();
    if (endpointString == NULL) {
      endpointString = parentSession().connectionEndpointName();
    }
    if (endpointString == NULL) break;

    // Now, convert this name to an address, if we can:
    NetAddressList addresses(endpointString);
    if (addresses.numAddresses() == 0) break;

    return *(unsigned*)(addresses.firstAddress()->data());
  } while (0);

  // No address known:
  return 0;
}

void MediaSubsession::setDestinations(unsigned defaultDestAddress) {
  // Get the destination address from the connection endpoint name
  // (This will be 0 if it's not known, in which case we use the default)
  unsigned destAddress = connectionEndpointAddress();
  if (destAddress == 0) destAddress = defaultDestAddress;
  struct in_addr destAddr; destAddr.s_addr = destAddress;

  // The destination TTL remains unchanged:
  int destTTL = ~0; // means: don't change

  if (fRTPSocket != NULL) {
    Port destPort(serverPortNum);
    fRTPSocket->changeDestinationParameters(destAddr, destPort, destTTL);
  }
  if (fRTCPSocket != NULL && !isSSM()) {
    // Note: For SSM sessions, the dest address for RTCP was already set.
    Port destPort(serverPortNum+1);
    fRTCPSocket->
      changeDestinationParameters(destAddr, destPort, destTTL);
  }
}

Boolean MediaSubsession::parseSDPLine_c(char const* sdpLine) {
  // Check for "c=IN IP4 <connection-endpoint>"
  // or "c=IN IP4 <connection-endpoint>/<ttl+numAddresses>"
  // (Later, do something with <ttl+numAddresses> also #####)
  char* connectionEndpointName = parseCLine(sdpLine);
  if (connectionEndpointName != NULL) {
    delete[] fConnectionEndpointName;
    fConnectionEndpointName = connectionEndpointName;
    return True;
  }

  return False;
}

Boolean MediaSubsession::parseSDPAttribute_rtpmap(char const* sdpLine) {
  // Check for a "a=rtpmap:<fmt> <codec>/<freq>" line:
  // (Also check without the "/<freq>"; RealNetworks omits this)
  // Also check for a trailing "/<numChannels>".
  Boolean parseSuccess = False;

  unsigned rtpmapPayloadFormat;
  char* codecName = strDupSize(sdpLine); // ensures we have enough space
  unsigned rtpTimestampFrequency = 0;
  unsigned numChannels = 1;
  if (sscanf(sdpLine, "a=rtpmap: %u %[^/]/%u/%u",
	     &rtpmapPayloadFormat, codecName, &rtpTimestampFrequency,
	     &numChannels) == 4
      || sscanf(sdpLine, "a=rtpmap: %u %[^/]/%u",
	     &rtpmapPayloadFormat, codecName, &rtpTimestampFrequency) == 3
      || sscanf(sdpLine, "a=rtpmap: %u %s",
		&rtpmapPayloadFormat, codecName) == 2) {
    parseSuccess = True;
    if (rtpmapPayloadFormat == fRTPPayloadFormat) {
      // This "rtpmap" matches our payload format, so set our
      // codec name and timestamp frequency:
      // (First, make sure the codec name is upper case)
      for (char* p = codecName; *p != '\0'; ++p) {
	*p = toupper(*p);
      }
      delete[] fCodecName; fCodecName = strDup(codecName);
      fRTPTimestampFrequency = rtpTimestampFrequency;
      fNumChannels = numChannels;
    }
  }
  delete[] codecName;

  return parseSuccess;
}

Boolean MediaSubsession::parseSDPAttribute_control(char const* sdpLine) {
  // Check for a "a=control:<control-path>" line:
  Boolean parseSuccess = False;

  char* controlPath = strDupSize(sdpLine); // ensures we have enough space
  if (sscanf(sdpLine, "a=control: %s", controlPath) == 1) {
    parseSuccess = True;
    delete[] fControlPath; fControlPath = strDup(controlPath);
  }
  delete[] controlPath;

  return parseSuccess;
}

Boolean MediaSubsession::parseSDPAttribute_range(char const* sdpLine) {
  // Check for a "a=range:npt=<startTime>-<endTime>" line:
  // (Later handle other kinds of "a=range" attributes also???#####)
  Boolean parseSuccess = False;

  float playEndTime;
  if (parseRangeAttribute(sdpLine, playEndTime)) {
    parseSuccess = True;
    if (playEndTime > fPlayEndTime) {
      fPlayEndTime = playEndTime;
      if (playEndTime > fParent.playEndTime()) {
	fParent.playEndTime() = playEndTime;
      }
    }
  }

  return parseSuccess;
}

Boolean MediaSubsession::parseSDPAttribute_fmtp(char const* sdpLine) {
  // Check for a "a=fmtp:" line:
  // TEMP: We check only for a handful of expected parameter names #####
  // Later: (i) check that payload format number matches; #####
  //        (ii) look for other parameters also (generalize?) #####  
  do {
    if (strncmp(sdpLine, "a=fmtp:", 7) != 0) break; sdpLine += 7;
    while (isdigit(*sdpLine)) ++sdpLine;

    // The remaining "sdpLine" should be a sequence of
    //     <name>=<value>;
    // parameter assignments.  Look at each of these.
    // First, convert the line to lower-case, to ease comparison:
    char* const lineCopy = strDup(sdpLine); char* line = lineCopy;
    for (char* c = line; *c != '\0'; ++c) *c = tolower(*c);
    while (*line != '\0' && *line != '\r' && *line != '\n') {
      unsigned u;
      char* valueStr = strDupSize(line);
      if (sscanf(line, " auxiliarydatasizelength = %u", &u) == 1) {
	fAuxiliarydatasizelength = u;
      } else if (sscanf(line, " constantduration = %u", &u) == 1) {
	fConstantduration = u;
      } else if (sscanf(line, " constantsize; = %u", &u) == 1) {
	fConstantsize = u;
      } else if (sscanf(line, " crc = %u", &u) == 1) {
	fCRC = u;
      } else if (sscanf(line, " ctsdeltalength = %u", &u) == 1) {
	fCtsdeltalength = u;
      } else if (sscanf(line, " de-interleavebuffersize = %u", &u) == 1) {
	fDe_interleavebuffersize = u;
      } else if (sscanf(line, " dtsdeltalength = %u", &u) == 1) {
	fDtsdeltalength = u;
      } else if (sscanf(line, " indexdeltalength = %u", &u) == 1) {
	fIndexdeltalength = u;
      } else if (sscanf(line, " indexlength = %u", &u) == 1) {
	fIndexlength = u;
      } else if (sscanf(line, " interleaving = %u", &u) == 1) {
	fInterleaving = u;
      } else if (sscanf(line, " maxdisplacement = %u", &u) == 1) {
	fMaxdisplacement = u;
      } else if (sscanf(line, " objecttype = %u", &u) == 1) {
	fObjecttype = u;
      } else if (sscanf(line, " octet-align = %u", &u) == 1) {
	fOctetalign = u;
      } else if (sscanf(line, " profile-level-id = %u", &u) == 1) {
	fProfile_level_id = u;
      } else if (sscanf(line, " robust-sorting = %u", &u) == 1) {
	fRobustsorting = u;
      } else if (sscanf(line, " sizelength = %u", &u) == 1) {
	fSizelength = u;
      } else if (sscanf(line, " streamstateindication = %u", &u) == 1) {
	fStreamstateindication = u;
      } else if (sscanf(line, " streamtype = %u", &u) == 1) {
	fStreamtype = u;
      } else if (sscanf(line, " cpresent = %u", &u) == 1) {
	fCpresent = u != 0;
      } else if (sscanf(line, " randomaccessindication = %u", &u) == 1) {
	fRandomaccessindication = u != 0;
      } else if (sscanf(line, " config = %[^; \t\r\n]", valueStr) == 1) {
	delete[] fConfig; fConfig = strDup(valueStr);
      } else if (sscanf(line, " mode = %[^; \t\r\n]", valueStr) == 1) {
	delete[] fMode; fMode = strDup(valueStr);
      } else if (sscanf(sdpLine, " sprop-parameter-sets = %[^; \t\r\n]", valueStr) == 1) {
	// Note: We used "sdpLine" here, because the value is case-sensitive.
	delete[] fSpropParameterSets; fSpropParameterSets = strDup(valueStr); 
      } else {
	// Some of the above parameters are Boolean.  Check whether the parameter
	// names appear alone, without a "= 1" at the end:
	if (sscanf(line, " %[^; \t\r\n]", valueStr) == 1) {
	  if (strcmp(valueStr, "octet-align") == 0) {
	    fOctetalign = 1;
	  } else if (strcmp(valueStr, "cpresent") == 0) {
            fCpresent = True;
	  } else if (strcmp(valueStr, "crc") == 0) {
	    fCRC = 1;
	  } else if (strcmp(valueStr, "robust-sorting") == 0) {
	    fRobustsorting = 1;
	  } else if (strcmp(valueStr, "randomaccessindication") == 0) {
	    fRandomaccessindication = True;
	  }
	}
      }
      delete[] valueStr;

      // Move to the next parameter assignment string:
      while (*line != '\0' && *line != '\r' && *line != '\n'
	     && *line != ';') ++line;
      while (*line == ';') ++line;

      // Do the same with sdpLine; needed for finding case sensitive values:
      while (*sdpLine != '\0' && *sdpLine != '\r' && *sdpLine != '\n'
	     && *sdpLine != ';') ++sdpLine;
      while (*sdpLine == ';') ++sdpLine;
    }
    delete[] lineCopy;
    return True;
  } while (0);

  return False;
}

Boolean MediaSubsession
::parseSDPAttribute_source_filter(char const* sdpLine) {
  return parseSourceFilterAttribute(sdpLine, fSourceFilterAddr);
}

Boolean MediaSubsession::parseSDPAttribute_x_mct_slap(char const* sdpLine) {
  // Check for a "a=x-mct-slap:<slap-session-id> <stagger>" line:
  Boolean parseSuccess = False;

  int slapSessionId;
  int slapStagger;
  if (sscanf(sdpLine, "a=x-mct-slap: %d %d",
	     &slapSessionId, &slapStagger) == 2) {
    parseSuccess = True;
    fMCT_SLAP_SessionId = slapSessionId;
    fMCT_SLAP_Stagger = (unsigned)slapStagger;
  }

  return parseSuccess;
}

Boolean MediaSubsession::parseSDPAttribute_x_dimensions(char const* sdpLine) {
  // Check for a "a=x-dimensions:<width>,<height>" line:
  Boolean parseSuccess = False;

  int width, height;
  if (sscanf(sdpLine, "a=x-dimensions:%d,%d", &width, &height) == 2) {
    parseSuccess = True;
    fVideoWidth = (unsigned short)width;
    fVideoHeight = (unsigned short)height;
  }

  return parseSuccess;
}

Boolean MediaSubsession::parseSDPAttribute_x_framerate(char const* sdpLine) {
  // Check for a "a=x-framerate:<fps>" line:
  Boolean parseSuccess = False;

  int rate;
  if (sscanf(sdpLine, "a=x-framerate:%d", &rate) == 1) {
    parseSuccess = True;
    fVideoFPS = (unsigned)rate;
  }

  return parseSuccess;
}