void JPEGVideoRTPSink
::doSpecialFrameHandling(unsigned fragmentationOffset,
			 unsigned char* /*frameStart*/,
			 unsigned /*numBytesInFrame*/,
			 struct timeval frameTimestamp,
			 unsigned numRemainingBytes) {
  // Our source is known to be a JPEGVideoSource
  JPEGVideoSource* source = (JPEGVideoSource*)fSource; 
  if (source == NULL) return; // sanity check

  u_int8_t mainJPEGHeader[8]; // the special header

  mainJPEGHeader[0] = 0; // Type-specific
  mainJPEGHeader[1] = fragmentationOffset >> 16;
  mainJPEGHeader[2] = fragmentationOffset >> 8;
  mainJPEGHeader[3] = fragmentationOffset;
  mainJPEGHeader[4] = source->type();
  mainJPEGHeader[5] = source->qFactor();
  mainJPEGHeader[6] = source->width();
  mainJPEGHeader[7] = source->height();
  setSpecialHeaderBytes(mainJPEGHeader, sizeof mainJPEGHeader);

  if (fragmentationOffset == 0 && source->qFactor() >= 128) {
    // There is also a Quantization Header:
    u_int8_t precision;
    u_int16_t length;
    u_int8_t const* quantizationTables
      = source->quantizationTables(precision, length);
    
    unsigned const quantizationHeaderSize = 4 + length;
    u_int8_t* quantizationHeader = new u_int8_t[quantizationHeaderSize];

    quantizationHeader[0] = 0; // MBZ
    quantizationHeader[1] = precision;
    quantizationHeader[2] = length >> 8;
    quantizationHeader[3] = length&0xFF;
    if (quantizationTables != NULL) { // sanity check
      for (u_int16_t i = 0; i < length; ++i) {
	quantizationHeader[4+i] = quantizationTables[i];
      }
    }

    setSpecialHeaderBytes(quantizationHeader, quantizationHeaderSize,
			  sizeof mainJPEGHeader /* start position */);
    delete[] quantizationHeader;
  }
Beispiel #2
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void JPEGVideoRTPSink
::doSpecialFrameHandling(unsigned fragmentationOffset,
                         unsigned char* /*frameStart*/,
                         unsigned /*numBytesInFrame*/,
                         struct timeval framePresentationTime,
                         unsigned numRemainingBytes) {
  // Our source is known to be a JPEGVideoSource
  JPEGVideoSource* source = (JPEGVideoSource*)fSource;
  if (source == NULL) return; // sanity check

  u_int8_t mainJPEGHeader[8]; // the special header
  u_int8_t const type = source->type();

  mainJPEGHeader[0] = 0; // Type-specific
  mainJPEGHeader[1] = fragmentationOffset >> 16;
  mainJPEGHeader[2] = fragmentationOffset >> 8;
  mainJPEGHeader[3] = fragmentationOffset;
  mainJPEGHeader[4] = type;
  mainJPEGHeader[5] = source->qFactor();
  mainJPEGHeader[6] = source->width();
  mainJPEGHeader[7] = source->height();
  setSpecialHeaderBytes(mainJPEGHeader, sizeof mainJPEGHeader);

  unsigned restartMarkerHeaderSize = 0; // by default
  if (type >= 64 && type <= 127) {
    // There is also a Restart Marker Header:
    restartMarkerHeaderSize = 4;
    u_int16_t const restartInterval = source->restartInterval(); // should be non-zero

    u_int8_t restartMarkerHeader[4];
    restartMarkerHeader[0] = restartInterval>>8;
    restartMarkerHeader[1] = restartInterval&0xFF;
    restartMarkerHeader[2] = restartMarkerHeader[3] = 0xFF; // F=L=1; Restart Count = 0x3FFF

    setSpecialHeaderBytes(restartMarkerHeader, restartMarkerHeaderSize,
                          sizeof mainJPEGHeader/* start position */);
  }