mp3aduinterleaving.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

/**********
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the terms of the GNU Lesser General Public License as published by the
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option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)

This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
more details.

You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
**********/
// "liveMedia"
// Copyright (c) 1996-2004 Live Networks, Inc.  All rights reserved.
// Interleaving of MP3 ADUs
// Implementation

#include "MP3ADUinterleaving.hh"
#include "MP3ADUdescriptor.hh"

#include <string.h>

#ifdef TEST_LOSS
#include "GroupsockHelper.hh"
#endif

////////// Interleaving //////////

Interleaving::Interleaving(unsigned cycleSize,
			   unsigned char const* cycleArray)
  : fCycleSize(cycleSize) {
  for (unsigned i = 0; i < fCycleSize; ++i) {
    fInverseCycle[cycleArray[i]] = i;
  }
}

Interleaving::~Interleaving() {
}

////////// MP3ADUinterleaverBase //////////

MP3ADUinterleaverBase::MP3ADUinterleaverBase(UsageEnvironment& env,
					     FramedSource* inputSource)
  : FramedFilter(env, inputSource) {
}
MP3ADUinterleaverBase::~MP3ADUinterleaverBase() {
}

FramedSource* MP3ADUinterleaverBase::getInputSource(UsageEnvironment& env,
						    char const* inputSourceName) {
  FramedSource* inputSource;
  if (!FramedSource::lookupByName(env, inputSourceName, inputSource))
    return NULL;
  
  if (strcmp(inputSource->MIMEtype(), "audio/MPA-ROBUST") != 0) {
    env.setResultMsg(inputSourceName, " is not an MP3 ADU source");
    return NULL;
  }
  
  return inputSource;
}

void MP3ADUinterleaverBase::afterGettingFrame(void* clientData,
					      unsigned numBytesRead,
					      unsigned /*numTruncatedBytes*/,
					      struct timeval presentationTime,
					      unsigned durationInMicroseconds) {
  MP3ADUinterleaverBase* interleaverBase = (MP3ADUinterleaverBase*)clientData;
  // Finish up after reading:
  interleaverBase->afterGettingFrame(numBytesRead,
				     presentationTime, durationInMicroseconds);

  // Then, continue to deliver an outgoing frame:
  interleaverBase->doGetNextFrame();
}


////////// InterleavingFrames (definition) //////////

class InterleavingFrames {
public:
  InterleavingFrames(unsigned maxCycleSize);
  virtual ~InterleavingFrames();

  Boolean haveReleaseableFrame();
  void getIncomingFrameParams(unsigned char index,
			      unsigned char*& dataPtr,
			      unsigned& bytesAvailable);
  void getReleasingFrameParams(unsigned char index,
			       unsigned char*& dataPtr,
			       unsigned& bytesInUse,
			       struct timeval& presentationTime,
			       unsigned& durationInMicroseconds);
  void setFrameParams(unsigned char index,
		      unsigned char icc, unsigned char ii,
		      unsigned frameSize, struct timeval presentationTime,
		      unsigned durationInMicroseconds);
  unsigned nextIndexToRelease() {return fNextIndexToRelease;}
  void releaseNext();

private:
  unsigned fMaxCycleSize;
  unsigned fNextIndexToRelease;
  class InterleavingFrameDescriptor* fDescriptors;
};

////////// MP3ADUinterleaver //////////


MP3ADUinterleaver::MP3ADUinterleaver(UsageEnvironment& env,
				     Interleaving const& interleaving,
				     FramedSource* inputSource)
  : MP3ADUinterleaverBase(env, inputSource),
    fInterleaving(interleaving),
    fFrames(new InterleavingFrames(interleaving.cycleSize())),
    fII(0), fICC(0) {
}

MP3ADUinterleaver::~MP3ADUinterleaver() {
  delete fFrames;
}

MP3ADUinterleaver* MP3ADUinterleaver::createNew(UsageEnvironment& env,
						Interleaving const& interleaving,
						FramedSource* inputSource) {
  return new MP3ADUinterleaver(env, interleaving, inputSource);
}

void MP3ADUinterleaver::doGetNextFrame() {
  // If there's a frame immediately available, deliver it, otherwise get new
  // frames from the source until one's available:
  if (fFrames->haveReleaseableFrame()) {
    releaseOutgoingFrame();

    // Call our own 'after getting' function.  Because we're not a 'leaf'
    // source, we can call this directly, without risking infinite recursion.
    afterGetting(this);
  } else {
    fPositionOfNextIncomingFrame = fInterleaving.lookupInverseCycle(fII);
    unsigned char* dataPtr;
    unsigned bytesAvailable;
    fFrames->getIncomingFrameParams(fPositionOfNextIncomingFrame,
				    dataPtr, bytesAvailable);

    // Read the next incoming frame (asynchronously)
    fInputSource->getNextFrame(dataPtr, bytesAvailable,
			       &MP3ADUinterleaverBase::afterGettingFrame, this,
			       handleClosure, this);
  }
}

void MP3ADUinterleaver::releaseOutgoingFrame() {
  unsigned char* fromPtr;
  fFrames->getReleasingFrameParams(fFrames->nextIndexToRelease(),
				   fromPtr, fFrameSize,
				   fPresentationTime, fDurationInMicroseconds);

  if (fFrameSize > fMaxSize) {
    fNumTruncatedBytes = fFrameSize - fMaxSize;
    fFrameSize = fMaxSize;
  }
  memmove(fTo, fromPtr, fFrameSize);

  fFrames->releaseNext();
}

void MP3ADUinterleaver::afterGettingFrame(unsigned numBytesRead,
					  struct timeval presentationTime,
					  unsigned durationInMicroseconds) {
  // Set the (icc,ii) and frame size of the newly-read frame:
  fFrames->setFrameParams(fPositionOfNextIncomingFrame,
			  fICC, fII, numBytesRead,
			  presentationTime, durationInMicroseconds);

  // Prepare our counters for the next frame:
  if (++fII == fInterleaving.cycleSize()) {
    fII = 0;
    fICC = (fICC+1)%8;
  }
}

////////// DeinterleavingFrames (definition) //////////

class DeinterleavingFrames {
public:
  DeinterleavingFrames();
  virtual ~DeinterleavingFrames();
  
  Boolean haveReleaseableFrame();
  void getIncomingFrameParams(unsigned char*& dataPtr,
			      unsigned& bytesAvailable);
  void getIncomingFrameParamsAfter(unsigned frameSize,
				   struct timeval presentationTime,
				   unsigned durationInMicroseconds,
				   unsigned char& icc, unsigned char& ii);
  void getReleasingFrameParams(unsigned char*& dataPtr,
			       unsigned& bytesInUse,
			       struct timeval& presentationTime,
			       unsigned& durationInMicroseconds);
  void moveIncomingFrameIntoPlace();
  void releaseNext();
  void startNewCycle();

private:
  unsigned fNextIndexToRelease;
  Boolean fHaveEndedCycle;
  unsigned fIIlastSeen;
  unsigned fMinIndexSeen, fMaxIndexSeen; // actually, max+1
  class DeinterleavingFrameDescriptor* fDescriptors;
};

////////// MP3ADUdeinterleaver //////////

MP3ADUdeinterleaver::MP3ADUdeinterleaver(UsageEnvironment& env,
					 FramedSource* inputSource)
  : MP3ADUinterleaverBase(env, inputSource),
    fFrames(new DeinterleavingFrames),
    fIIlastSeen(~0), fICClastSeen(~0) {
}

MP3ADUdeinterleaver::~MP3ADUdeinterleaver() {
}

MP3ADUdeinterleaver* MP3ADUdeinterleaver::createNew(UsageEnvironment& env,
						    FramedSource* inputSource) {
  return new MP3ADUdeinterleaver(env, inputSource);
}

void MP3ADUdeinterleaver::doGetNextFrame() {
  // If there's a frame immediately available, deliver it, otherwise get new
  // frames from the source until one's available:
  if (fFrames->haveReleaseableFrame()) {
    releaseOutgoingFrame();

    // Call our own 'after getting' function.  Because we're not a 'leaf'
    // source, we can call this directly, without risking infinite recursion.
    afterGetting(this);
  } else {
#ifdef TEST_LOSS
  NOTE: This code no longer works, because it uses synchronous reads,
  which are no longer supported. 
    static unsigned const framesPerPacket = 3;
    static unsigned const frameCount = 0;
    static Boolean packetIsLost;
    while (1) {
      unsigned packetCount = frameCount/framesPerPacket;
      if ((frameCount++)%framesPerPacket == 0) {
	packetIsLost = (our_random()%10 == 0); // simulate 10% packet loss #####
      }

      if (packetIsLost) {
	// Read and discard the next input frame (that would be part of
	// a lost packet):
	unsigned char dummyBuf[2000];
	unsigned numBytesRead;
	struct timeval presentationTime;