liveMedia/MPEG4LATMAudioRTPSource.cpp File Reference

#include "MPEG4LATMAudioRTPSource.hh"

Include dependency graph for MPEG4LATMAudioRTPSource.cpp:

Go to the source code of this file.

Data Structures
class	LATMBufferedPacket
class	LATMBufferedPacketFactory
Functions
static Boolean	getNibble (char const *&configStr, unsigned char &resultNibble)
static Boolean	getByte (char const *&configStr, unsigned char &resultByte)
Boolean	parseStreamMuxConfigStr (char const *configStr, Boolean &audioMuxVersion, Boolean &allStreamsSameTimeFraming, unsigned char &numSubFrames, unsigned char &numProgram, unsigned char &numLayer, unsigned char *&audioSpecificConfig, unsigned &audioSpecificConfigSize)
unsigned char *	parseStreamMuxConfigStr (char const *configStr, unsigned &audioSpecificConfigSize)
unsigned char *	parseGeneralConfigStr (char const *configStr, unsigned &configSize)

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Function Documentation

static Boolean getByte	(	char const *&	configStr,
		unsigned char &	resultByte
	)			[static]

Definition at line 147 of file MPEG4LATMAudioRTPSource.cpp.

References False, getNibble(), and True.

Referenced by parseGeneralConfigStr(), and parseStreamMuxConfigStr().

                                                                          {
  resultByte = 0; // by default, in case parsing fails

  unsigned char firstNibble;
  if (!getNibble(configStr, firstNibble)) return False;
  resultByte = firstNibble<<4;

  unsigned char secondNibble = 0;
  if (!getNibble(configStr, secondNibble) && configStr[0] != '\0') {
    // There's a second nibble, but it's malformed
    return False;
  }
  resultByte |= secondNibble;

  return True;
}

static Boolean getNibble	(	char const *&	configStr,
		unsigned char &	resultNibble
	)			[static]

Definition at line 128 of file MPEG4LATMAudioRTPSource.cpp.

References False, and True.

Referenced by getByte().

                                                      {
  char c = configStr[0];
  if (c == '\0') return False; // we've reached the end

  if (c >= '0' && c <= '9') {
    resultNibble = c - '0';
  } else if (c >= 'A' && c <= 'F') {
    resultNibble = 10 + c - 'A';
  } else if (c >= 'a' && c <= 'f') {
    resultNibble = 10 + c - 'a';
  } else {
    return False;
  }

  ++configStr; // move to the next nibble
  return True;
}

unsigned char* parseGeneralConfigStr	(	char const *	configStr,
		unsigned &	configSize
	)

Definition at line 241 of file MPEG4LATMAudioRTPSource.cpp.

References getByte(), and NULL.

Referenced by QuickTimeFileSink::addAtom_hdlr2(), MPEG4ESVideoRTPSink::MPEG4ESVideoRTPSink(), samplingFrequencyFromAudioSpecificConfig(), MPEG4VideoStreamFramer::setConfigInfo(), and setupStreams().

00242                                                         :
00243                                      unsigned& configSize) {
00244   unsigned char* config = NULL;
00245   do {
00246     if (configStr == NULL) break;
00247     configSize = (strlen(configStr)+1)/2;
00248 
00249     config = new unsigned char[configSize];
00250     if (config == NULL) break;
00251 
00252     unsigned i;
00253     for (i = 0; i < configSize; ++i) {
00254       if (!getByte(configStr, config[i])) break;
00255     }
00256     if (i != configSize) break; // part of the string was bad
00257 
00258     return config;
00259   } while (0);
00260 
00261   configSize = 0;
00262   delete[] config;
00263   return NULL;
00264 }
}

unsigned char* parseStreamMuxConfigStr	(	char const *	configStr,
		unsigned &	audioSpecificConfigSize
	)

Definition at line 223 of file MPEG4LATMAudioRTPSource.cpp.

References NULL, and parseStreamMuxConfigStr().

                                                          :
                                       unsigned& audioSpecificConfigSize) {
  Boolean audioMuxVersion, allStreamsSameTimeFraming;
  unsigned char numSubFrames, numProgram, numLayer;
  unsigned char* audioSpecificConfig;

  if (!parseStreamMuxConfigStr(configStr,
                               audioMuxVersion, allStreamsSameTimeFraming,
                               numSubFrames, numProgram, numLayer,
                               audioSpecificConfig, audioSpecificConfigSize)) {
    audioSpecificConfigSize = 0;
    return NULL;
  }

  return audioSpecificConfig;
}

Boolean parseStreamMuxConfigStr	(	char const *	configStr,
		Boolean &	audioMuxVersion,
		Boolean &	allStreamsSameTimeFraming,
		unsigned char &	numSubFrames,
		unsigned char &	numProgram,
		unsigned char &	numLayer,
		unsigned char *&	audioSpecificConfig,
		unsigned &	audioSpecificConfigSize
	)

Definition at line 165 of file MPEG4LATMAudioRTPSource.cpp.

References False, getByte(), NULL, and True.

                                            :
                        Boolean& audioMuxVersion,
                        Boolean& allStreamsSameTimeFraming,
                        unsigned char& numSubFrames,
                        unsigned char& numProgram,
                        unsigned char& numLayer,
                        unsigned char*& audioSpecificConfig,
                        unsigned& audioSpecificConfigSize) {
  // Set default versions of the result parameters:
  audioMuxVersion = 0;
  allStreamsSameTimeFraming = 1;
  numSubFrames = numProgram = numLayer = 0;
  audioSpecificConfig = NULL;
  audioSpecificConfigSize = 0;

  do {
    if (configStr == NULL) break;

    unsigned char nextByte;

    if (!getByte(configStr, nextByte)) break;
    audioMuxVersion = (nextByte&0x80)>>7;
    if (audioMuxVersion != 0) break;

    allStreamsSameTimeFraming = (nextByte&0x40)>>6;
    numSubFrames = (nextByte&0x3F);

    if (!getByte(configStr, nextByte)) break;
    numProgram = (nextByte&0xF0)>>4;

    numLayer = (nextByte&0x0E)>>1;

    // The one remaining bit, and the rest of the string,
    // are used for "audioSpecificConfig":
    unsigned char remainingBit = nextByte&1;

    unsigned ascSize = (strlen(configStr)+1)/2 + 1;
    audioSpecificConfig = new unsigned char[ascSize];

    Boolean parseSuccess;
    unsigned i = 0;
    do {
      nextByte = 0;
      parseSuccess = getByte(configStr, nextByte);
      audioSpecificConfig[i++] = (remainingBit<<7)|((nextByte&0xFE)>>1);
      remainingBit = nextByte&1;
    } while (parseSuccess);
    if (i != ascSize) break; // part of the remaining string was bad

    audioSpecificConfigSize = ascSize;
    return True; // parsing succeeded
  } while (0);

  delete[] audioSpecificConfig;
  return False; // parsing failed
}

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