庖丁解牛-----Live555源码彻底解密(根据OpenRTSP讲解)

OpenRtsp中写H264文件注意的地方：
 
OpenRtsp客户端包括OpenRtsp.cpp和playCommon.cpp 两个文件
 
1）接受buffer保存到文件
void
H264VideoFileSink::afterGettingFrame(unsignedframeSize,unsignednumTruncatedBytes,structtimeval
presentationTime) {
  unsigned
char const start_code[4] = {0x00, 0x00, 0x00, 0x01};
 
  if (!fHaveWrittenFirstFrame) {
    // If we have PPS/SPS NAL units encoded in a "sprop parameter string", prepend these to the file:
    unsigned
numSPropRecords;
    SPropRecord*
sPropRecords = parseSPropParameterSets(fSPropParameterSetsStr,numSPropRecords);
    for (unsignedi = 0;i <
numSPropRecords; ++i) {
      addData(start_code, 4,presentationTime);
      addData(sPropRecords[i].sPropBytes,sPropRecords[i].sPropLength,presentationTime);
    }
    delete[]
sPropRecords;
    fHaveWrittenFirstFrame =
True; // for next time
  }
 
  // Write the input data to the file, with the start code in front:
  addData(start_code, 4,presentationTime);
 
  // Call the parent class to complete the normal file write with the input data:
  FileSink::afterGettingFrame(frameSize,numTruncatedBytes,presentationTime);
}
 
2）获取到路径名
              // Create an output file for each desired stream:
                   char
outFileName[1000];
                   if (singleMedium ==NULL) {
                       // Output file name is
                       //     "<filename-prefix><medium_name>-<codec_name>-<counter>"
                       static
unsigned streamCounter = 0;
                       //outFileName为文件名
                       snprintf(outFileName,sizeofoutFileName,"%s%s-%s-%d",
                            fileNamePrefix,subsession->mediumName(),
                            subsession->codecName(), ++streamCounter);
                   } else {
                       sprintf(outFileName,"stdout");
                   }
 
3）保存文件
void
FileSink::afterGettingFrame(unsignedframeSize,
                    unsigned
numTruncatedBytes,
                    struct
timeval presentationTime) {
  if (numTruncatedBytes > 0) {
    envir() <<
"FileSink::afterGettingFrame(): The input frame data was too large for our buffer size ("
         << fBufferSize <<
").  "
            << numTruncatedBytes <<" bytes of trailing data was dropped! Correct this by increasing the \"bufferSize\" parameter in the \"createNew()\" call to at least "
            << fBufferSize +
numTruncatedBytes << "\n";
  }
  addData(fBuffer,frameSize,presentationTime);
 
  if (fOutFid ==NULL ||fflush(fOutFid) ==EOF)
{
    // The output file has closed. 
Handle this the same way as if the input source had closed:
    if (fSource !=NULL)fSource->stopGettingFrames();
    onSourceClosure(this);
    return;
  }
 
  if (fPerFrameFileNameBuffer !=NULL) {
    if (fOutFid !=NULL) {fclose(fOutFid);fOutFid
=NULL; }
  }
 
  // Then try getting the next frame:
  continuePlaying();
}
 
 
1）   写文件
void
FileSink::addData(unsignedcharconst*
data, unsigned
dataSize,
                struct
timeval presentationTime) {
  if (fPerFrameFileNameBuffer !=NULL) {
    // Special case: Open a new file on-the-fly for this frame
    sprintf(fPerFrameFileNameBuffer,"%s-%lu.%06lu",fPerFrameFileNamePrefix,
         presentationTime.tv_sec,presentationTime.tv_usec);
    fOutFid =
OpenOutputFile(envir(),
fPerFrameFileNameBuffer);
  }
 
  // Write to our file:
#ifdef
TEST_LOSS
  static unsigned const framesPerPacket = 10;
  static unsigned const frameCount = 0;
  static Boolean const packetIsLost;
  if ((frameCount++)%framesPerPacket == 0) {
    packetIsLost = (our_random()%10 == 0); // simulate 10% packet loss #####
  }
 
  if (!packetIsLost)
#endif
  if (fOutFid !=NULL &&data !=NULL) {
    fwrite(data, 1,dataSize,fOutFid);
  }
}
 
其中  unsigned
char* fBuffer; 用来保存文件的Buff;
  fBuffer =
new unsigned char[bufferSize]; 缓冲区的size，默认多少？
 

 
#ifndef
_H264_VIDEO_FILE_SINK_HH
#define
_H264_VIDEO_FILE_SINK_HH
 
#ifndef
_FILE_SINK_HH
#include "FileSink.hh"
#endif
 
class
H264VideoFileSink: public
FileSink {
public:
  static
H264VideoFileSink* createNew(UsageEnvironment&env,char
const* fileName,
                         char
const* sPropParameterSetsStr =
NULL,
  // An optional 'SDP format' string (comma-separated Base64-encoded) representing SPS and/or PPS NAL-units to prepend to the output
                         unsigned bufferSize = 100000,
                         BooleanoneFilePerFrame =False);
  // See "FileSink.hh" for a description of these parameters.
 
protected:
  H264VideoFileSink(UsageEnvironment&env,FILE*
fid,
             char
const* sPropParameterSetsStr,
             unsigned
bufferSize, char
const* perFrameFileNamePrefix);
      // called only by createNew()
  virtual ~H264VideoFileSink();
 
protected:
// redefined virtual functions:
  virtual
void afterGettingFrame(unsignedframeSize,unsignednumTruncatedBytes,structtimeval
presentationTime);
 
private:
  char const*fSPropParameterSetsStr;
  Boolean
fHaveWrittenFirstFrame;
};
 
#endif
 
默认的是100k 可以修改，在OpenRtsp中修改unsignedfileSinkBufferSize = 1000000;           //modify by zh 100000 to 1000000
 
OpenRtsp还需要获取帧率的信息，进行录像，帧率的参数可以从OpenRtsp中进行修改;
unsigned
movieFPS = 30; // default                
//帧率信息modify by zhongh 15 to 30
 
相机1080p的 30帧，每秒1.18M
 
 
OpenRtsp将文件写成AVI的代码如下：
else if (outputAVIFile) {
              // Create an "AVIFileSink", to write to 'stdout':
 
              //如何将stdout修改成写avi 文件
              aviOut =
AVIFileSink::createNew(*env, *session,"d:\\test1.avi",
                   fileSinkBufferSize,
                   movieWidth,movieHeight,
                   movieFPS,              //帧率
                   packetLossCompensate);//包丢失补偿;
              if (aviOut ==NULL) {
                   *env <<
"Failed to create AVI file sink for stdout: " <<
env->getResultMsg();
                   shutdown();
              }
 
aviOut->startPlaying(sessionAfterPlaying,NULL);