multiframedrtpsink.cpp

H.264 RTSP 串流(live 555)視窗版本

/**********
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
Free Software Foundation; either version 2.1 of the License, or (at your
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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
**********/
// "liveMedia"
// Copyright (c) 1996-2010 Live Networks, Inc.  All rights reserved.
// RTP sink for a common kind of payload format: Those which pack multiple,
// complete codec frames (as many as possible) into each RTP packet.
// Implementation

#include "MultiFramedRTPSink.hh"
#include "GroupsockHelper.hh"

////////// MultiFramedRTPSink //////////

void MultiFramedRTPSink::setPacketSizes(unsigned preferredPacketSize,
					unsigned maxPacketSize) {
  if (preferredPacketSize > maxPacketSize || preferredPacketSize == 0) return;
      // sanity check

  delete fOutBuf;
  fOutBuf = new OutPacketBuffer(preferredPacketSize, maxPacketSize);
  fOurMaxPacketSize = maxPacketSize; // save value, in case subclasses need it
}

MultiFramedRTPSink::MultiFramedRTPSink(UsageEnvironment& env,
				       Groupsock* rtpGS,
				       unsigned char rtpPayloadType,
				       unsigned rtpTimestampFrequency,
				       char const* rtpPayloadFormatName,
				       unsigned numChannels)
  : RTPSink(env, rtpGS, rtpPayloadType, rtpTimestampFrequency,
	    rtpPayloadFormatName, numChannels),
  fOutBuf(NULL), fCurFragmentationOffset(0), fPreviousFrameEndedFragmentation(False) {
  setPacketSizes(1000, 1448);
      // Default max packet size (1500, minus allowance for IP, UDP, UMTP headers)
      // (Also, make it a multiple of 4 bytes, just in case that matters.)
}

MultiFramedRTPSink::~MultiFramedRTPSink() {
  delete fOutBuf;
}

void MultiFramedRTPSink
::doSpecialFrameHandling(unsigned /*fragmentationOffset*/,
			 unsigned char* /*frameStart*/,
			 unsigned /*numBytesInFrame*/,
			 struct timeval frameTimestamp,
			 unsigned /*numRemainingBytes*/) {
  // default implementation: If this is the first frame in the packet,
  // use its timestamp for the RTP timestamp:
  if (isFirstFrameInPacket()) {
    setTimestamp(frameTimestamp);
  }
}

Boolean MultiFramedRTPSink::allowFragmentationAfterStart() const {
  return False; // by default
}

Boolean MultiFramedRTPSink::allowOtherFramesAfterLastFragment() const {
  return False; // by default
}

Boolean MultiFramedRTPSink
::frameCanAppearAfterPacketStart(unsigned char const* /*frameStart*/,
				 unsigned /*numBytesInFrame*/) const {
  return True; // by default
}

unsigned MultiFramedRTPSink::specialHeaderSize() const {
  // default implementation: Assume no special header:
  return 0;
}

unsigned MultiFramedRTPSink::frameSpecificHeaderSize() const {
  // default implementation: Assume no frame-specific header:
  return 0;
}

unsigned MultiFramedRTPSink::computeOverflowForNewFrame(unsigned newFrameSize) const {
  // default implementation: Just call numOverflowBytes()
  return fOutBuf->numOverflowBytes(newFrameSize);
}

void MultiFramedRTPSink::setMarkerBit() {
  unsigned rtpHdr = fOutBuf->extractWord(0);
  rtpHdr |= 0x00800000;
  fOutBuf->insertWord(rtpHdr, 0);
}

void MultiFramedRTPSink::setTimestamp(struct timeval timestamp) {
  // First, convert the timestamp to a 32-bit RTP timestamp:
  fCurrentTimestamp = convertToRTPTimestamp(timestamp);

  // Then, insert it into the RTP packet:
  fOutBuf->insertWord(fCurrentTimestamp, fTimestampPosition);
}

void MultiFramedRTPSink::setSpecialHeaderWord(unsigned word,
					      unsigned wordPosition) {
  fOutBuf->insertWord(word, fSpecialHeaderPosition + 4*wordPosition);
}

void MultiFramedRTPSink::setSpecialHeaderBytes(unsigned char const* bytes,
					       unsigned numBytes,
					       unsigned bytePosition) {
  fOutBuf->insert(bytes, numBytes, fSpecialHeaderPosition + bytePosition);
}

void MultiFramedRTPSink::setFrameSpecificHeaderWord(unsigned word,
						    unsigned wordPosition) {
  fOutBuf->insertWord(word, fCurFrameSpecificHeaderPosition + 4*wordPosition);
}

void MultiFramedRTPSink::setFrameSpecificHeaderBytes(unsigned char const* bytes,
						     unsigned numBytes,
						     unsigned bytePosition) {
  fOutBuf->insert(bytes, numBytes, fCurFrameSpecificHeaderPosition + bytePosition);
}

void MultiFramedRTPSink::setFramePadding(unsigned numPaddingBytes) {
  if (numPaddingBytes > 0) {
    // Add the padding bytes (with the last one being the padding size):
    unsigned char paddingBuffer[255]; //max padding
    memset(paddingBuffer, 0, numPaddingBytes);
    paddingBuffer[numPaddingBytes-1] = numPaddingBytes;
    fOutBuf->enqueue(paddingBuffer, numPaddingBytes);

    // Set the RTP padding bit:
    unsigned rtpHdr = fOutBuf->extractWord(0);
    rtpHdr |= 0x20000000;
    fOutBuf->insertWord(rtpHdr, 0);
  }
}

Boolean MultiFramedRTPSink::continuePlaying() {
  // Send the first packet.
  // (This will also schedule any future sends.)
  buildAndSendPacket(True);
  return True;
}

void MultiFramedRTPSink::stopPlaying() {
  fOutBuf->resetPacketStart();
  fOutBuf->resetOffset();
  fOutBuf->resetOverflowData();

  // Then call the default "stopPlaying()" function:
  MediaSink::stopPlaying();
}

void MultiFramedRTPSink::buildAndSendPacket(Boolean isFirstPacket) {
  fIsFirstPacket = isFirstPacket;

  // Set up the RTP header:
  unsigned rtpHdr = 0x80000000; // RTP version 2
  rtpHdr |= (fRTPPayloadType<<16);
  rtpHdr |= fSeqNo; // sequence number
  fOutBuf->enqueueWord(rtpHdr);

  // Note where the RTP timestamp will go.
  // (We can't fill this in until we start packing payload frames.)
  fTimestampPosition = fOutBuf->curPacketSize();
  fOutBuf->skipBytes(4); // leave a hole for the timestamp

  fOutBuf->enqueueWord(SSRC());

  // Allow for a special, payload-format-specific header following the
  // RTP header:
  fSpecialHeaderPosition = fOutBuf->curPacketSize();
  fSpecialHeaderSize = specialHeaderSize();
  fOutBuf->skipBytes(fSpecialHeaderSize);

  // Begin packing as many (complete) frames into the packet as we can:
  fTotalFrameSpecificHeaderSizes = 0;
  fNoFramesLeft = False;
  fNumFramesUsedSoFar = 0;
  packFrame();
}

void MultiFramedRTPSink::packFrame() {
  // Get the next frame.

  // First, see if we have an overflow frame that was too big for the last pkt
  if (fOutBuf->haveOverflowData()) {
    // Use this frame before reading a new one from the source
    unsigned frameSize = fOutBuf->overflowDataSize();
    struct timeval presentationTime = fOutBuf->overflowPresentationTime();
    unsigned durationInMicroseconds = fOutBuf->overflowDurationInMicroseconds();
    fOutBuf->useOverflowData();

    afterGettingFrame1(frameSize, 0, presentationTime, durationInMicroseconds);
  } else {
    // Normal case: we need to read a new frame from the source
    if (fSource == NULL) return;

    fCurFrameSpecificHeaderPosition = fOutBuf->curPacketSize();
    fCurFrameSpecificHeaderSize = frameSpecificHeaderSize();