h264videortpsink.cpp

linux下的rtsp/rtp/rtcp协议栈源代码； c++写的

/**********
This library is free software; you can redistribute it and/or modify it under
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) 1996-2006 Live Networks, Inc.  All rights reserved.
// RTP sink for H.264 video (RFC 3984)
// Implementation

#include "H264VideoRTPSink.hh"
#include "H264VideoStreamFramer.hh"

////////// H264VideoRTPSink implementation //////////

H264VideoRTPSink
::H264VideoRTPSink(UsageEnvironment& env, Groupsock* RTPgs,
		   unsigned char rtpPayloadFormat,
		   unsigned profile_level_id,
		   char const* sprop_parameter_sets_str)
  : VideoRTPSink(env, RTPgs, rtpPayloadFormat, 90000, "H264"),
    fOurFragmenter(NULL) {
  // Set up the "a=fmtp:" SDP line for this stream:
  char const* fmtpFmt =
    "a=fmtp:%d packetization-mode=1"
    ";profile-level-id=%06X"
    ";sprop-parameter-sets=%s\r\n";
  unsigned fmtpFmtSize = strlen(fmtpFmt)
    + 3 /* max char len */
    + 8 /* max unsigned len in hex */
    + strlen(sprop_parameter_sets_str);
  char* fmtp = new char[fmtpFmtSize];
  sprintf(fmtp, fmtpFmt,
          rtpPayloadFormat,
	  profile_level_id,
          sprop_parameter_sets_str);
  fFmtpSDPLine = strDup(fmtp);
  delete[] fmtp;
}

H264VideoRTPSink::~H264VideoRTPSink() {
  delete[] fFmtpSDPLine;
  delete fOurFragmenter;
}

H264VideoRTPSink*
H264VideoRTPSink::createNew(UsageEnvironment& env, Groupsock* RTPgs,
			    unsigned char rtpPayloadFormat,
			    unsigned profile_level_id,
			    char const* sprop_parameter_sets_str) {
  return new H264VideoRTPSink(env, RTPgs, rtpPayloadFormat,
			      profile_level_id, sprop_parameter_sets_str);
}

Boolean H264VideoRTPSink::sourceIsCompatibleWithUs(MediaSource& source) {
  // Our source must be an appropriate framer:
  return source.isH264VideoStreamFramer();
}

Boolean H264VideoRTPSink::continuePlaying() {
  // First, check whether we have a 'fragmenter' class set up yet.
  // If not, create it now:
  if (fOurFragmenter == NULL) {
    fOurFragmenter = new H264FUAFragmenter(envir(), fSource, OutPacketBuffer::maxSize,
					   ourMaxPacketSize() - 12/*RTP hdr size*/);
    fSource = fOurFragmenter;
  }

  // Then call the parent class's implementation:
  return MultiFramedRTPSink::continuePlaying();
}

void H264VideoRTPSink::stopPlaying() {
  // First, call the parent class's implementation, to stop our fragmenter object
  // (and its source):
  MultiFramedRTPSink::stopPlaying();

  // Then, close our 'fragmenter' object:
  Medium::close(fOurFragmenter); fOurFragmenter = NULL;
}

void H264VideoRTPSink::doSpecialFrameHandling(unsigned /*fragmentationOffset*/,
					      unsigned char* /*frameStart*/,
					      unsigned /*numBytesInFrame*/,
					      struct timeval frameTimestamp,
					      unsigned /*numRemainingBytes*/) {
  // Set the RTP 'M' (marker) bit iff
  // 1/ The most recently delivered fragment was the end of
  //    (or the only fragment of) an NAL unit, and
  // 2/ This NAL unit was the last NAL unit of an 'access unit' (i.e. video frame).
  if (fOurFragmenter != NULL) {
    H264VideoStreamFramer* framerSource
      = (H264VideoStreamFramer*)(fOurFragmenter->inputSource());
    // This relies on our fragmenter's source being a "MPEG4VideoStreamFramer".
    if (fOurFragmenter->lastFragmentCompletedNALUnit()
	&& framerSource != NULL && framerSource->currentNALUnitEndsAccessUnit()) {
      setMarkerBit();
    }
  }

  setTimestamp(frameTimestamp);
}

Boolean H264VideoRTPSink
::frameCanAppearAfterPacketStart(unsigned char const* /*frameStart*/,
				 unsigned /*numBytesInFrame*/) const {
  return False;
}

char const* H264VideoRTPSink::auxSDPLine() {
  return fFmtpSDPLine;
}


////////// H264FUAFragmenter implementation //////////

H264FUAFragmenter::H264FUAFragmenter(UsageEnvironment& env,
				     FramedSource* inputSource,
				     unsigned inputBufferMax,
				     unsigned maxOutputPacketSize)
  : FramedFilter(env, inputSource),
    fInputBufferSize(inputBufferMax+1), fMaxOutputPacketSize(maxOutputPacketSize),
    fNumValidDataBytes(1), fCurDataOffset(1), fSaveNumTruncatedBytes(0),
    fLastFragmentCompletedNALUnit(True) {
  fInputBuffer = new unsigned char[fInputBufferSize];
}

H264FUAFragmenter::~H264FUAFragmenter() {
  delete[] fInputBuffer;
  fInputSource = NULL; // so that the subsequent ~FramedFilter doesn't delete it
}

void H264FUAFragmenter::doGetNextFrame() {
  if (fNumValidDataBytes == 1) {
    // We have no NAL unit data currently in the buffer.  Read a new one:
    fInputSource->getNextFrame(&fInputBuffer[1], fInputBufferSize - 1,
			       afterGettingFrame, this,
			       FramedSource::handleClosure, this);
  } else {
    // We have NAL unit data in the buffer.  There are three cases to consider:
    // 1. There is a new NAL unit in the buffer, and it's small enough to deliver
    //    to the RTP sink (as is).
    // 2. There is a new NAL unit in the buffer, but it's too large to deliver to
    //    the RTP sink in its entirety.  Deliver the first fragment of this data,
    //    as a FU-A packet, with one extra preceding header byte.
    // 3. There is a NAL unit in the buffer, and we've already delivered some
    //    fragment(s) of this.  Deliver the next fragment of this data,
    //    as a FU-A packet, with two extra preceding header bytes.

    if (fMaxSize < fMaxOutputPacketSize) { // shouldn't happen
      envir() << "H264FUAFragmenter::doGetNextFrame(): fMaxSize ("
	      << fMaxSize << ") is smaller than expected\n";
    } else {
      fMaxSize = fMaxOutputPacketSize;
    }

    fLastFragmentCompletedNALUnit = True; // by default
    if (fCurDataOffset == 1) { // case 1 or 2
      if (fNumValidDataBytes - 1 <= fMaxSize) { // case 1
	memmove(fTo, &fInputBuffer[1], fNumValidDataBytes - 1);
	fFrameSize = fNumValidDataBytes - 1;
	fCurDataOffset = fNumValidDataBytes;
      } else { // case 2
	// We need to send the NAL unit data as FU-A packets.  Deliver the first
	// packet now.  Note that we add FU indicator and FU header bytes to the front
	// of the packet (reusing the existing NAL header byte for the FU header).
	fInputBuffer[0] = (fInputBuffer[1] & 0xE0) | 28; // FU indicator
	fInputBuffer[1] = 0x80 | (fInputBuffer[1] & 0x1F); // FU header (with S bit)
	memmove(fTo, fInputBuffer, fMaxSize);
	fFrameSize = fMaxSize;
	fCurDataOffset += fMaxSize - 1;
	fLastFragmentCompletedNALUnit = False;
      }
    } else { // case 3
      // We are sending this NAL unit data as FU-A packets.  We've already sent the
      // first packet (fragment).  Now, send the next fragment.  Note that we add
      // FU indicator and FU header bytes to the front.  (We reuse these bytes that
      // we already sent for the first fragment, but clear the S bit, and add the E
      // bit if this is the last fragment.)
      fInputBuffer[fCurDataOffset-2] = fInputBuffer[0]; // FU indicator
      fInputBuffer[fCurDataOffset-1] = fInputBuffer[1]&~0x80; // FU header (no S bit)
      unsigned numBytesToSend = 2 + fNumValidDataBytes - fCurDataOffset;
      if (numBytesToSend > fMaxSize) {
	// We can't send all of the remaining data this time:
	numBytesToSend = fMaxSize;
	fLastFragmentCompletedNALUnit = False;
      } else {
	// This is the last fragment:
	fInputBuffer[fCurDataOffset-1] |= 0x40; // set the E bit in the FU header
	fNumTruncatedBytes = fSaveNumTruncatedBytes;
      }
      memmove(fTo, &fInputBuffer[fCurDataOffset-2], numBytesToSend);
      fFrameSize = numBytesToSend;
      fCurDataOffset += numBytesToSend - 2;
    }

    if (fCurDataOffset >= fNumValidDataBytes) {
      // We're done with this data.  Reset the pointers for receiving new data:
      fNumValidDataBytes = fCurDataOffset = 1;
    }

    // Complete delivery to the client:
    FramedSource::afterGetting(this);
  }
}

void H264FUAFragmenter::afterGettingFrame(void* clientData, unsigned frameSize,
					  unsigned numTruncatedBytes,
					  struct timeval presentationTime,
					  unsigned durationInMicroseconds) {
  H264FUAFragmenter* fragmenter = (H264FUAFragmenter*)clientData;
  fragmenter->afterGettingFrame1(frameSize, numTruncatedBytes, presentationTime,
				 durationInMicroseconds);
}

void H264FUAFragmenter::afterGettingFrame1(unsigned frameSize,
					   unsigned numTruncatedBytes,
					   struct timeval presentationTime,
					   unsigned durationInMicroseconds) {
  fNumValidDataBytes += frameSize;
  fSaveNumTruncatedBytes = numTruncatedBytes;
  fPresentationTime = presentationTime;
  fDurationInMicroseconds = durationInMicroseconds;

  // Deliver data to the client:
  doGetNextFrame();
}