h263plusvideostreamparser.cpp

linux下的rtsp/rtp/rtcp协议栈源代码； c++写的

/**********
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the terms of the GNU Lesser General Public License as published by the
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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.
// Author Bernhard Feiten
// A filter that breaks up an H.263plus video stream into frames.
// Based on MPEG4IP/mp4creator/h263.c

#include "H263plusVideoStreamParser.hh"
#include "H263plusVideoStreamFramer.hh"
//#include <string.h>
//#include "GroupsockHelper.hh"


H263plusVideoStreamParser::H263plusVideoStreamParser(
                              H263plusVideoStreamFramer* usingSource,
                              FramedSource* inputSource)
                              : StreamParser(inputSource,
                                   FramedSource::handleClosure,
                                   usingSource,
                                   &H263plusVideoStreamFramer::continueReadProcessing,
                                   usingSource),
                                fUsingSource(usingSource),
                                fnextTR(0),
                                fcurrentPT(0)
{
   memset(fStates, 0, sizeof(fStates));
   memset(&fNextInfo, 0, sizeof(fNextInfo));
   memset(&fCurrentInfo, 0, sizeof(fCurrentInfo));
   memset(&fMaxBitrateCtx, 0, sizeof(fMaxBitrateCtx));
   memset(fNextHeader,0, H263_REQUIRE_HEADER_SIZE_BYTES);
}

///////////////////////////////////////////////////////////////////////////////
H263plusVideoStreamParser::~H263plusVideoStreamParser()
{
}

///////////////////////////////////////////////////////////////////////////////
void H263plusVideoStreamParser::restoreSavedParserState()
{
   StreamParser::restoreSavedParserState();
   fTo = fSavedTo;
   fNumTruncatedBytes = fSavedNumTruncatedBytes;
}

///////////////////////////////////////////////////////////////////////////////
void H263plusVideoStreamParser::setParseState()
{
   fSavedTo = fTo;
   fSavedNumTruncatedBytes = fNumTruncatedBytes;
   saveParserState();  // Needed for the parsing process in StreamParser
}


///////////////////////////////////////////////////////////////////////////////
void H263plusVideoStreamParser::registerReadInterest(
                                   unsigned char* to,
                                   unsigned maxSize)
{
   fStartOfFrame = fTo = fSavedTo = to;
   fLimit = to + maxSize;
   fMaxSize = maxSize;
   fNumTruncatedBytes = fSavedNumTruncatedBytes = 0;
}

///////////////////////////////////////////////////////////////////////////////
// parse() ,  derived from H263Creator of MPEG4IP, h263.c
unsigned H263plusVideoStreamParser::parse(u_int64_t & currentDuration)
{

//   u_int8_t       frameBuffer[H263_BUFFER_SIZE]; // The input buffer
                 // Pointer which tells LoadNextH263Object where to read data to
//   u_int8_t*      pFrameBuffer = fTo + H263_REQUIRE_HEADER_SIZE_BYTES;
   u_int32_t      frameSize;        // The current frame size
                                // Pointer to receive address of the header data
//   u_int8_t*      pCurrentHeader;// = pFrameBuffer;
//   u_int64_t      currentDuration;  // The current frame's duration
   u_int8_t       trDifference;     // The current TR difference
                                   // The previous TR difference
//   u_int8_t       prevTrDifference = H263_BASIC_FRAME_RATE;
//   u_int64_t      totalDuration = 0;// Duration accumulator
//   u_int64_t      avgBitrate;       // Average bitrate
//   u_int64_t      totalBytes = 0;   // Size accumulator


   try    // The get data routines of the class FramedFilter returns an error when
   {      // the buffer is empty. This occurs at the beginning and at the end of the file.
      fCurrentInfo = fNextInfo;

      // Parse 1 frame
      // For the first time, only the first frame's header is returned.
      // The second time the full first frame is returned
      frameSize = parseH263Frame(); 

      currentDuration = 0;
      if ((frameSize > 0)){ 
         // We were able to acquire a frame from the input.

         // Parse the returned frame header (if any)
         if (!ParseShortHeader(fTo, &fNextInfo))
           ;// fprintf(stderr,"H263plusVideoStreamParser: Fatal error\n");
         trDifference = GetTRDifference(fNextInfo.tr, fCurrentInfo.tr);

         // calculate the current frame duration
         currentDuration = CalculateDuration(trDifference);

         // Accumulate the frame's size and duration for avgBitrate calculation
         //totalDuration += currentDuration;
         //totalBytes += frameSize;
         //  If needed, recalculate bitrate information
         //    if (h263Bitrates)
         //GetMaxBitrate(&fMaxBitrateCtx, frameSize, prevTrDifference);
         //prevTrDifference = trDifference;
      }
   } catch (int /*e*/) {
#ifdef DEBUG
      fprintf(stderr, "H263plusVideoStreamParser::parse() EXCEPTION (This is normal behavior - *not* an error)\n");
#endif
      frameSize=0;
   }

   setParseState(); // Needed for the parsing process in StreamParser

   return frameSize;
}


///////////////////////////////////////////////////////////////////////////////
// parseH263Frame derived from LoadNextH263Object of MPEG4IP 
// - service routine that reads a single frame from the input file.
// It shall fill the input buffer with data up until - and including - the
// next start code and shall report back both the number of bytes read and a
// pointer to the next start code. The first call to this function shall only
// yield a pointer with 0 data bytes and the last call to this function shall
// only yield data bytes with a NULL pointer as the next header.
//
// TODO: This function only supports valid bit streams. Upon error, it fails
// without the possibility to recover. A Better idea would be to skip frames
// until a parsable frame is read from the file.
//
// Parameters:
//      ppNextHeader - output parameter that upon return points to the location
//                     of the next frame's head in the buffer.
//                     This pointer shall be NULL for the last frame read.
// Returns the total number of bytes read.
// Uses FrameFileSource intantiated by constructor.
///////////////////////////////////////////////////////////////////////////////
int H263plusVideoStreamParser::parseH263Frame( )
{
   char     row = 0;
   u_int8_t * bufferIndex = fTo;
   // The buffer end which will allow the loop to leave place for
   // the additionalBytesNeeded
   u_int8_t * bufferEnd = fTo + fMaxSize - ADDITIONAL_BYTES_NEEDED - 1;	

   memcpy(fTo, fNextHeader, H263_REQUIRE_HEADER_SIZE_BYTES);
   bufferIndex += H263_REQUIRE_HEADER_SIZE_BYTES;
   

   // The state table and the following loop implements a state machine enabling
   // us to read bytes from the file until (and inclusing) the requested
   // start code (00 00 8X) is found

   // Initialize the states array, if it hasn't been initialized yet...
   if (!fStates[0][0]) {
      // One 00 was read
      fStates[0][0] = 1;
      // Two sequential 0x00 ware read
      fStates[1][0] = fStates[2][0] = 2;
      // A full start code was read
      fStates[2][128] = fStates[2][129] = fStates[2][130] = fStates[2][131] = -1;
   }

   // Read data from file into the output buffer until either a start code
   // is found, or the end of file has been reached.
   do {
      *bufferIndex = get1Byte();
   } while ((bufferIndex < bufferEnd) &&                    // We have place in the buffer
            ((row = fStates[(unsigned char)row][*(bufferIndex++)]) != -1)); // Start code was not found

   if (row != -1) {
      fprintf(stderr, "%s: Buffer too small (%u)\n",
         "h263reader:", bufferEnd - fTo + ADDITIONAL_BYTES_NEEDED);
      return 0;
   }

   // Cool ... now we have a start code
   // Now we just have to read the additionalBytesNeeded
   getBytes(bufferIndex, ADDITIONAL_BYTES_NEEDED);
   memcpy(fNextHeader, bufferIndex - H263_STARTCODE_SIZE_BYTES, H263_REQUIRE_HEADER_SIZE_BYTES);

	int sz = bufferIndex - fTo - H263_STARTCODE_SIZE_BYTES;

   if (sz == 5) // first frame
      memcpy(fTo, fTo+H263_REQUIRE_HEADER_SIZE_BYTES, H263_REQUIRE_HEADER_SIZE_BYTES);

   return sz;
}


////////////////////////////////////////////////////////////////////////////////
// ParseShortHeader - service routine that accepts a buffer containing a frame
// header and extracts relevant codec information from it.
//
// NOTE: the first bit in the following commnets is 0 (zero).
//
//       0                   1                   2                   3
//       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
//      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//      |      PSC (Picture Start Code=22 bits)     |  (TR=8 bits)  |   >
//      |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0|               |1 0>
//      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//      <   (PTYPE=13 bits)   |
//      <. . .|(FMT)|Z|. . . .|
//      +-+-+-+-+-+-+-+-+-+-+-+
//      -> PTYPE.FMT contains a width/height identification
//      -> PTYPE.Z   is 1 for P-Frames, 0 for I-Frames
//      Note: When FMT is 111, there is an extended PTYPE...
//
// Inputs:
//      headerBuffer - pointer to the current header buffer
//      outputInfoStruct - pointer to the structure receiving the data
// Outputs:
//      This function returns a structure of important codec-specific
//      information (The Temporal Reference bits, width & height of the current
//      frame and the sync - or "frame type" - bit. It reports success or
//      failure to the calling function.
////////////////////////////////////////////////////////////////////////////////
bool H263plusVideoStreamParser::ParseShortHeader(
                                   u_int8_t *headerBuffer,
                                   H263INFO *outputInfoStruct)
{
   u_int8_t fmt = 0;
   // Extract temporal reference (TR) from the buffer (bits 22-29 inclusive)
   outputInfoStruct->tr  = (headerBuffer[2] << 6) & 0xC0; // 2 LS bits out of the 3rd byte
   outputInfoStruct->tr |= (headerBuffer[3] >> 2) & 0x3F; // 6 MS bits out of the 4th byte
   // Extract the FMT part of PTYPE from the buffer (bits 35-37 inclusive)
   fmt = (headerBuffer[4] >> 2) & 0x07; // bits 3-5 ouf of the 5th byte
   // If PTYPE is not supported, return a failure notice to the calling function
   // FIXME: PLUSPTYPE is not supported
   if (fmt == 0x07) {
      return false;
   }
   // If PTYPE is supported, calculate the current width and height according to
   // a predefined table
   if (!GetWidthAndHeight(fmt, &(outputInfoStruct->width),
                               &(outputInfoStruct->height))) {
      return false;
   }
   // Extract the frame-type bit, which is the 9th bit of PTYPE (bit 38)
   outputInfoStruct->isSyncFrame = !(headerBuffer[4] & 0x02);

  return true;
}

////////////////////////////////////////////////////////////////////////////////
// GetMaxBitrate- service routine that accepts frame information and
// derives bitrate information from it. This function uses a sliding window
// technique to calculate the maximum bitrates in any window of 1 second
// inside the file.
// The sliding window is implemented with a table of bitrates for the last
// second (30 entries - one entry per TR unit).
//
// Inputs:
//      ctx - context for this function
//      frameSize - the size of the current frame in bytes
//      frameTRDiff - the "duration" of the frame in TR units
// Outputs:
//      This function returns the up-to-date maximum bitrate
////////////////////////////////////////////////////////////////////////////////
void H263plusVideoStreamParser::GetMaxBitrate( MaxBitrate_CTX *ctx,
                                               u_int32_t      frameSize,