rtmpdump代码分析 转

RTMPdump 源代码分析 1: main()函数





rtmpdump 是一个用来处理 RTMP 流媒体的工具包,支持 rtmp://, rtmpt://, rtmpe://, rtmpte://, and rtmps:// 等。

之前在学习RTMP协议的时候,发现没有讲它源代码的,只好自己分析,现在打算把自己学习的成果写出来,可能结果不一定都对,

先暂且记录一下。









使用RTMPdump下载一个流媒体的大致流程是这样的:





RTMP_Init();          //初始化结构体

InitSockets();        //初始化Socket

RTMP_ParseURL();      //解析输入URL

RTMP_SetupStream();   //一些设置

fopen();              //打开文件,准备写入





RTMP_Connect();       //建立NetConnection

RTMP_ConnectStream(); //建立NetStream

Download();           //下载函数





RTMP_Close();         //关闭连接

fclose();             //关闭文件

CleanupSockets();     //清理Socket









其中Download()主要是使用RTMP_Read()进行下载的。





注:可以参考:RTMP流媒体播放过程





下面贴上自己注释的RTMPDump源代码。注意以下几点:





1.此RTMPDump已经被移植进VC 2010 的 MFC的工程,所以main()函数已经被改名为rtmpdump(),而且参数也改了,传进来一个MFC窗口的句柄。

不过功能没怎么改(控制台程序移植到MFC以后,main()就不是程序的入口了,所以main()名字改成什么是无所谓的)





2.里面有很多提取信息的代码形如:rtmp.dlg->AppendCInfo("开始初始化Socket...");

这些代码是我为了获取RTMP信息而自己加的,并不影响程序的执行。









int rtmpdump(LPVOID lpParam,int argc,char **argv)

{



  extern char *optarg;

  //一定要设置,否则只能运行一次

  extern int optind;

  optind=0;

  int nStatus = RD_SUCCESS;

  double percent = 0;

  double duration = 0.0;





  int nSkipKeyFrames = DEF_SKIPFRM; // skip this number of keyframes when resuming






  int bOverrideBufferTime = FALSE; // if the user specifies a buffer time override this is true

  int bStdoutMode = TRUE; // if true print the stream directly to stdout, messages go to stderr

  int bResume = FALSE; // true in resume mode

  uint32_t dSeek = 0; // seek position in resume mode, 0 otherwise

  uint32_t bufferTime = DEF_BUFTIME;





  // meta header and initial frame for the resume mode (they are read from the file and compared with

  // the stream we are trying to continue

  char *metaHeader = 0;

  uint32_t nMetaHeaderSize = 0;





  // video keyframe for matching

  char *initialFrame = 0;

  uint32_t nInitialFrameSize = 0;

  int initialFrameType = 0; // tye: audio or video





  AVal hostname = { 0, 0 };

  AVal playpath = { 0, 0 };

  AVal subscribepath = { 0, 0 };

  int port = -1;

  int protocol = RTMP_PROTOCOL_UNDEFINED;

  int retries = 0;

  int bLiveStream = FALSE; // 是直播流吗? then we can't seek/resume

  int bHashes = FALSE; // display byte counters not hashes by default





  long int timeout = DEF_TIMEOUT; // timeout connection after 120 seconds

  uint32_t dStartOffset = 0; // 非直播流搜寻点seek position in non-live mode

  uint32_t dStopOffset = 0;

  RTMP rtmp = { 0 };





  AVal swfUrl = { 0, 0 };

  AVal tcUrl = { 0, 0 };

  AVal pageUrl = { 0, 0 };

  AVal app = { 0, 0 };

  AVal auth = { 0, 0 };

  AVal swfHash = { 0, 0 };

  uint32_t swfSize = 0;

  AVal flashVer = { 0, 0 };

  AVal sockshost = { 0, 0 };





#ifdef CRYPTO

  int swfAge = 30; /* 30 days for SWF cache by default */

  int swfVfy = 0;

  unsigned char hash[RTMP_SWF_HASHLEN];

#endif





  char *flvFile = 0;





  signal(SIGINT, sigIntHandler);

  signal(SIGTERM, sigIntHandler);

#ifndef WIN32

  signal(SIGHUP, sigIntHandler);

  signal(SIGPIPE, sigIntHandler);

  signal(SIGQUIT, sigIntHandler);

#endif





  RTMP_debuglevel = RTMP_LOGINFO;





  //首先搜寻“ --quiet”选项

  int index = 0;

  while (index < argc)

  {

    if (strcmp(argv[index], "--quiet") == 0

|| strcmp(argv[index], "-q") == 0)

       RTMP_debuglevel = RTMP_LOGCRIT;

       index++;

  }

#define RTMPDUMP_VERSION "1.0"

  RTMP_LogPrintf("RTMP流媒体下载 %s\n", RTMPDUMP_VERSION);

  RTMP_LogPrintf

    ("2012 雷霄骅 中国传媒大学/信息工程学院/通信与信息系统/数字电视技术\n");

  //RTMP_LogPrintf("输入 -h 获取命令选项\n");

  RTMP_Init(&rtmp);

  

  //句柄-----------------------------

  rtmp.dlg=(CSpecialPRTMPDlg *)lpParam;

  //---------------------------------

  

  //----------------------

  rtmp.dlg->AppendCInfo("开始初始化Socket...");

  //-----------------------------

  if (!InitSockets())

  {

    //----------------------

    rtmp.dlg->AppendCInfo("初始化Socket失败!");

    //-----------------------------

    RTMP_Log(RTMP_LOGERROR, "Couldn't load sockets support on your platform, exiting!");

    return RD_FAILED;

  }

  

  //----------------------

  rtmp.dlg->AppendCInfo("成功初始化Socket");

  //-----------------------------

  /* sleep(30); */









  int opt;

/*  struct option longopts[] = {

    {"help", 0, NULL, 'h'},

    {"host", 1, NULL, 'n'},

    {"port", 1, NULL, 'c'},

    {"socks", 1, NULL, 'S'},

    {"protocol", 1, NULL, 'l'},

    {"playpath", 1, NULL, 'y'},

    {"playlist", 0, NULL, 'Y'},

    {"rtmp", 1, NULL, 'r'},

    {"swfUrl", 1, NULL, 's'},

    {"tcUrl", 1, NULL, 't'},

    {"pageUrl", 1, NULL, 'p'},

    {"app", 1, NULL, 'a'},

    {"auth", 1, NULL, 'u'},

    {"conn", 1, NULL, 'C'},

#ifdef CRYPTO

    {"swfhash", 1, NULL, 'w'},

    {"swfsize", 1, NULL, 'x'},

    {"swfVfy", 1, NULL, 'W'},

    {"swfAge", 1, NULL, 'X'},

#endif

    {"flashVer", 1, NULL, 'f'},

    {"live", 0, NULL, 'v'},

    {"flv", 1, NULL, 'o'},

    {"resume", 0, NULL, 'e'},

    {"timeout", 1, NULL, 'm'},

    {"buffer", 1, NULL, 'b'},

    {"skip", 1, NULL, 'k'},

    {"subscribe", 1, NULL, 'd'},

    {"start", 1, NULL, 'A'},

    {"stop", 1, NULL, 'B'},

    {"token", 1, NULL, 'T'},

    {"hashes", 0, NULL, '#'},

    {"debug", 0, NULL, 'z'},

    {"quiet", 0, NULL, 'q'},

    {"verbose", 0, NULL, 'V'},

    {0, 0, 0, 0}

  };*/

  //分析命令行参数,注意用法。

  //选项都是一个字母,后面有冒号的代表该选项还有相关参数

  //一直循环直到获取所有的opt

  while ((opt =

 getopt/*_long*/(argc, argv,

     "hVveqzr:s:t:p:a:b:f:o:u:C:n:c:l:y:Ym:k:d:A:B:T:w:x:W:X:S:#"/*,

     longopts, NULL*/)) != -1)

  {

    //不同的选项做不同的处理

    switch (opt)

    {

      case 'h':

usage(argv[0]);

return RD_SUCCESS;

#ifdef CRYPTO

      case 'w':

      {

int res = hex2bin(optarg, &swfHash.av_val);

if (res != RTMP_SWF_HASHLEN)

{

          swfHash.av_val = NULL;

 RTMP_Log(RTMP_LOGWARNING,

            "Couldn't parse swf hash hex string, not hexstring or not %d bytes, ignoring!", RTMP_SWF_HASHLEN);

}

swfHash.av_len = RTMP_SWF_HASHLEN;

break;

      }

      case 'x':

      {

int size = atoi(optarg);

if (size <= 0)

{

 RTMP_Log(RTMP_LOGERROR, "SWF Size must be at least 1, ignoring\n");

}

        else

{

          swfSize = size;

}

break;

      }

      case 'W':

STR2AVAL(swfUrl, optarg);

swfVfy = 1;

        break;

      case 'X':

      {

int num = atoi(optarg);

if (num < 0)

{

          RTMP_Log(RTMP_LOGERROR, "SWF Age must be non-negative, ignoring\n");

}

else

{

          swfAge = num;

}

      }

      break;

#endif

      case 'k':

nSkipKeyFrames = atoi(optarg);

if (nSkipKeyFrames < 0)

{

 RTMP_Log(RTMP_LOGERROR,

            "Number of keyframes skipped must be greater or equal zero, using zero!");

 nSkipKeyFrames = 0;

}

        else

{

 RTMP_Log(RTMP_LOGDEBUG, "Number of skipped key frames for resume: %d",nSkipKeyFrames);

}

break;

      case 'b':

      {

int32_t bt = atol(optarg);

if (bt < 0)

        {

          RTMP_Log(RTMP_LOGERROR,

            "Buffer time must be greater than zero, ignoring the specified value %d!",

            bt);

        }

        else

        {

          bufferTime = bt;

          bOverrideBufferTime = TRUE;

        }

        break;

      }

      //直播流

      case 'v':

        //----------------

        rtmp.dlg->AppendCInfo("该RTMP的URL是一个直播流");

        //----------------

        bLiveStream = TRUE; // no seeking or resuming possible!

        break;

      case 'd':

STR2AVAL(subscribepath, optarg);

break;

      case 'n':

STR2AVAL(hostname, optarg);

break;

      case 'c':

port = atoi(optarg);

break;

      case 'l':

        protocol = atoi(optarg);

if (protocol < RTMP_PROTOCOL_RTMP || protocol > RTMP_PROTOCOL_RTMPTS)

        {

 RTMP_Log(RTMP_LOGERROR, "Unknown protocol specified: %d", protocol);

 return RD_FAILED;

}

break;

      case 'y':

STR2AVAL(playpath, optarg);

break;

      case 'Y':

RTMP_SetOpt(&rtmp, &av_playlist, (AVal *)&av_true);

break;

      //路径参数-r

      case 'r':

      {

        AVal parsedHost, parsedApp, parsedPlaypath;

        unsigned int parsedPort = 0;

        int parsedProtocol = RTMP_PROTOCOL_UNDEFINED;





        //解析URL。注optarg指向参数(URL)

        RTMP_LogPrintf("RTMP URL : %s\n",optarg);

        //----------------

        rtmp.dlg->AppendCInfo("解析RTMP的URL...");

        //----------------

        if (!RTMP_ParseURL

            (optarg, &parsedProtocol, &parsedHost, &parsedPort,

             &parsedPlaypath, &parsedApp))

        {

          //----------------

          rtmp.dlg->AppendCInfo("解析RTMP的URL失败!");

          //----------------

          RTMP_Log(RTMP_LOGWARNING, "无法解析 url (%s)!",optarg);

        }

        else

        {

          //----------------

          rtmp.dlg->AppendCInfo("解析RTMP的URL成功");

          //----------------

          //把解析出来的数据赋值

          if (!hostname.av_len)

            hostname = parsedHost;

          if (port == -1)

            port = parsedPort;

          if (playpath.av_len == 0 && parsedPlaypath.av_len)

          {

            playpath = parsedPlaypath;

          }

          if (protocol == RTMP_PROTOCOL_UNDEFINED)

            protocol = parsedProtocol;

          if (app.av_len == 0 && parsedApp.av_len)

          {

            app = parsedApp;

          }

        }

        break;

      }

      case 's':

        STR2AVAL(swfUrl, optarg);

        break;

      case 't':

        STR2AVAL(tcUrl, optarg);

        break;

      case 'p':

        STR2AVAL(pageUrl, optarg);

        break;

      case 'a':

        STR2AVAL(app, optarg);

        break;

      case 'f':

        STR2AVAL(flashVer, optarg);

        break;

        //指定输出文件

      case 'o':

        flvFile = optarg;

        if (strcmp(flvFile, "-"))

          bStdoutMode = FALSE;





        break;

      case 'e':

        bResume = TRUE;

        break;

      case 'u':

        STR2AVAL(auth, optarg);

        break;

      case 'C': {

        AVal av;

        STR2AVAL(av, optarg);

        if (!RTMP_SetOpt(&rtmp, &av_conn, &av))

        {

          RTMP_Log(RTMP_LOGERROR, "Invalid AMF parameter: %s", optarg);

          return RD_FAILED;

        }

      }

        break;

      case 'm':

        timeout = atoi(optarg);

        break;

      case 'A':

        dStartOffset = (int) (atof(optarg) * 1000.0);

        break;

      case 'B':

        dStopOffset = (int) (atof(optarg) * 1000.0);

        break;

      case 'T': {

        AVal token;

        STR2AVAL(token, optarg);

        RTMP_SetOpt(&rtmp, &av_token, &token);

      }

        break;

      case '#':

        bHashes = TRUE;

        break;

      case 'q':

        RTMP_debuglevel = RTMP_LOGCRIT;

        break;

      case 'V':

        RTMP_debuglevel = RTMP_LOGDEBUG;

        break;

      case 'z':

        RTMP_debuglevel = RTMP_LOGALL;

        break;

      case 'S':

        STR2AVAL(sockshost, optarg);

        break;

      default:

        RTMP_LogPrintf("unknown option: %c\n", opt);

        usage(argv[0]);

        return RD_FAILED;

        break;

      }

  }





  if (!hostname.av_len)

  {

    RTMP_Log(RTMP_LOGERROR,

      "您必须指定 主机名(hostname) (--host) 或 url (-r \"rtmp://host[:port]/playpath\") 包含 a hostname");

    return RD_FAILED;

  }

  if (playpath.av_len == 0)

  {

    RTMP_Log(RTMP_LOGERROR,

"您必须指定 播放路径(playpath) (--playpath) 或 url (-r \"rtmp://host[:port]/playpath\") 包含 a playpath");

    return RD_FAILED;

  }





  if (protocol == RTMP_PROTOCOL_UNDEFINED)

  {

    RTMP_Log(RTMP_LOGWARNING,

"您没有指定 协议(protocol) (--protocol) 或 rtmp url (-r), 默认协议 RTMP");

    protocol = RTMP_PROTOCOL_RTMP;

  }

  if (port == -1)

  {

    RTMP_Log(RTMP_LOGWARNING,"您没有指定 端口(port) (--port) 或 rtmp url (-r), 默认端口 1935");

    port = 0;

  }

  if (port == 0)

  {

    if (protocol & RTMP_FEATURE_SSL)

      port = 443;

    else if (protocol & RTMP_FEATURE_HTTP)

      port = 80;

    else

      port = 1935;

  }





  if (flvFile == 0)

  {

    RTMP_Log(RTMP_LOGWARNING,

 "请指定一个输出文件 (-o filename), using stdout");

    bStdoutMode = TRUE;

  }





  if (bStdoutMode && bResume)

  {

    RTMP_Log(RTMP_LOGWARNING,

 "Can't resume in stdout mode, ignoring --resume option");

    bResume = FALSE;

  }





  if (bLiveStream && bResume)

  {

    RTMP_Log(RTMP_LOGWARNING, "Can't resume live stream, ignoring --resume option");

    bResume = FALSE;

  }





#ifdef CRYPTO

  if (swfVfy)

  {

    if (RTMP_HashSWF(swfUrl.av_val, (unsigned int *)&swfSize, hash, swfAge) == 0)

    {

      swfHash.av_val = (char *)hash;

      swfHash.av_len = RTMP_SWF_HASHLEN;

    }

  }





  if (swfHash.av_len == 0 && swfSize > 0)

  {

    RTMP_Log(RTMP_LOGWARNING,

"Ignoring SWF size, supply also the hash with --swfhash");

    swfSize = 0;

  }





  if (swfHash.av_len != 0 && swfSize == 0)

  {

    RTMP_Log(RTMP_LOGWARNING,

      "Ignoring SWF hash, supply also the swf size  with --swfsize");

    swfHash.av_len = 0;

    swfHash.av_val = NULL;

  }

#endif





  if (tcUrl.av_len == 0)

  {

    char str[512] = { 0 };





    tcUrl.av_len = snprintf(str, 511, "%s://%.*s:%d/%.*s",

RTMPProtocolStringsLower[protocol], hostname.av_len,

         hostname.av_val, port, app.av_len, app.av_val);

    tcUrl.av_val = (char *) malloc(tcUrl.av_len + 1);

    strcpy(tcUrl.av_val, str);

  }





  int first = 1;





  // User defined seek offset

  if (dStartOffset > 0)

  {

    //直播流

    if (bLiveStream)

    {

      RTMP_Log(RTMP_LOGWARNING,"Can't seek in a live stream, ignoring --start option");

      dStartOffset = 0;

    }

  }

  //----------------

  rtmp.dlg->AppendCInfo("开始初始化RTMP连接的参数...");

  //----------------

  //设置

  RTMP_SetupStream(&rtmp, protocol, &hostname, port, &sockshost, &playpath,

  &tcUrl, &swfUrl, &pageUrl, &app, &auth, &swfHash, swfSize,

  &flashVer, &subscribepath, dSeek, dStopOffset, bLiveStream, timeout);

  //此处设置参数-----------------

  rtmp.dlg->AppendCInfo("成功初始化RTMP连接的参数");

  //-----------------------------

  char *temp=(char *)malloc(MAX_URL_LENGTH);





  memcpy(temp,rtmp.Link.hostname.av_val,rtmp.Link.hostname.av_len);

  temp[rtmp.Link.hostname.av_len]='\0';

  rtmp.dlg->AppendB_R_L_Info("主机名",temp);





  itoa(rtmp.Link.port,temp,10);

  rtmp.dlg->AppendB_R_L_Info("端口号",temp);





  memcpy(temp,rtmp.Link.app.av_val,rtmp.Link.app.av_len);

  temp[rtmp.Link.app.av_len]='\0';

  rtmp.dlg->AppendB_R_L_Info("应用程序",temp);





  memcpy(temp,rtmp.Link.playpath.av_val,rtmp.Link.playpath.av_len);

  temp[rtmp.Link.playpath.av_len]='\0';

  rtmp.dlg->AppendB_R_L_Info("路径",temp);









  //-----------------------------





  /* Try to keep the stream moving if it pauses on us */

  if (!bLiveStream && !(protocol & RTMP_FEATURE_HTTP))

    rtmp.Link.lFlags |= RTMP_LF_BUFX;





  off_t size = 0;





  // ok,我们必须获得timestamp of the last keyframe (only keyframes are seekable) / last audio frame (audio only streams)

  if (bResume)

  {

    //打开文件,输出的文件(Resume)

    nStatus =OpenResumeFile(flvFile, &file, &size, &metaHeader, &nMetaHeaderSize,

      &duration);

    if (nStatus == RD_FAILED)

      goto clean;





    if (!file)

    {

      // file does not exist, so go back into normal mode

      bResume = FALSE; // we are back in fresh file mode (otherwise finalizing file won't be done)

    }

    else

    {

      //获取最后一个关键帧

      nStatus = GetLastKeyframe(file, nSkipKeyFrames,

        &dSeek, &initialFrame,

        &initialFrameType, &nInitialFrameSize);

      if (nStatus == RD_FAILED)

      {

        RTMP_Log(RTMP_LOGDEBUG, "Failed to get last keyframe.");

        goto clean;

      }





      if (dSeek == 0)

      {

        RTMP_Log(RTMP_LOGDEBUG,

           "Last keyframe is first frame in stream, switching from resume to normal mode!");

        bResume = FALSE;

      }

    }

  }

  //如果输出文件不存在

  if (!file)

  {

    if (bStdoutMode)

    {

      //直接输出到stdout

      file = stdout;

      SET_BINMODE(file);

    }

    else

    {

      //打开一个文件

      //w+b 读写打开或建立一个二进制文件,允许读和写。

      //-----------------

      rtmp.dlg->AppendCInfo("创建输出文件...");

      //-----------------------------

      file = fopen(flvFile, "w+b");

      if (file == 0)

      {

        //-----------------

        rtmp.dlg->AppendCInfo("创建输出文件失败!");

        //-----------------------------

        RTMP_LogPrintf("Failed to open file! %s\n", flvFile);

        return RD_FAILED;

      }

      rtmp.dlg->AppendCInfo("成功创建输出文件");

    }

  }





#ifdef _DEBUG

  netstackdump = fopen("netstackdump", "wb");

  netstackdump_read = fopen("netstackdump_read", "wb");

#endif





  while (!RTMP_ctrlC)

  {

    RTMP_Log(RTMP_LOGDEBUG, "Setting buffer time to: %dms", bufferTime);

    //设置Buffer时间

    //-----------------

    rtmp.dlg->AppendCInfo("设置缓冲(Buffer)的时间");

    //-----------------------------

    RTMP_SetBufferMS(&rtmp, bufferTime);

    //第一次执行

    if (first)

    {

      first = 0;

      RTMP_LogPrintf("开始建立连接!\n");

      //-----------------

      rtmp.dlg->AppendCInfo("开始建立连接(NetConnection)...");

      //-----------------------------

      //建立连接(Connect)

      if (!RTMP_Connect(&rtmp, NULL))

      {

        //-----------------

        rtmp.dlg->AppendCInfo("建立连接(NetConnection)失败!");

        //-----------------------------

        nStatus = RD_FAILED;

        break;

      }

      //-----------------

      rtmp.dlg->AppendCInfo("成功建立连接(NetConnection)");

      //-----------------------------

      //RTMP_Log(RTMP_LOGINFO, "已链接...");





      // User defined seek offset

      if (dStartOffset > 0)

      {

        // Don't need the start offset if resuming an existing file

        if (bResume)

        {

          RTMP_Log(RTMP_LOGWARNING,

            "Can't seek a resumed stream, ignoring --start option");

          dStartOffset = 0;

        }

        else

        {

          dSeek = dStartOffset;

        }

      }





      // Calculate the length of the stream to still play

      if (dStopOffset > 0)

      {

        // Quit if start seek is past required stop offset

        if (dStopOffset <= dSeek)

        {

          RTMP_LogPrintf("Already Completed\n");

          nStatus = RD_SUCCESS;

          break;

        }

      }

      //创建流(Stream)(发送connect命令消息后处理传来的数据)

      itoa(rtmp.m_inChunkSize,temp,10);

      rtmp.dlg->AppendB_R_Info("输入Chunk大小",temp);

      itoa(rtmp.m_outChunkSize,temp,10);

      rtmp.dlg->AppendB_R_Info("输出Chunk大小",temp);

      itoa(rtmp.m_stream_id,temp,10);

      rtmp.dlg->AppendB_R_Info("Stream ID",temp);

      itoa(rtmp.m_nBufferMS,temp,10);

      rtmp.dlg->AppendB_R_Info("Buffer时长(ms)",temp);

      itoa(rtmp.m_nServerBW,temp,10);

      rtmp.dlg->AppendB_R_Info("ServerBW",temp);

      itoa(rtmp.m_nClientBW,temp,10);

      rtmp.dlg->AppendB_R_Info("ClientBW",temp);

      itoa((int)rtmp.m_fEncoding,temp,10);

      rtmp.dlg->AppendB_R_Info("命令消息编码方法",temp);

      itoa((int)rtmp.m_fDuration,temp,10);

      rtmp.dlg->AppendB_R_Info("时长(s)",temp);





      rtmp.dlg->ShowBInfo();

      free(temp);

      //-----------------

      rtmp.dlg->AppendCInfo("开始建立网络流(NetStream)");

      //-----------------------------

      if (!RTMP_ConnectStream(&rtmp, dSeek))

      {

        //-----------------

        rtmp.dlg->AppendCInfo("建立网络流(NetStream)失败!");

        //-----------------

        nStatus = RD_FAILED;

        break;

      }

      //-----------------

      rtmp.dlg->AppendCInfo("成功建立网络流(NetStream)!");

      //-----------------

    }

    else

    {

      nInitialFrameSize = 0;





      if (retries)

      {

        RTMP_Log(RTMP_LOGERROR, "Failed to resume the stream\n\n");

        if (!RTMP_IsTimedout(&rtmp))

          nStatus = RD_FAILED;

        else

          nStatus = RD_INCOMPLETE;

          break;

      }

      RTMP_Log(RTMP_LOGINFO, "Connection timed out, trying to resume.\n\n");

      /* Did we already try pausing, and it still didn't work? */

      if (rtmp.m_pausing == 3)

      {

        /* Only one try at reconnecting... */

        retries = 1;

        dSeek = rtmp.m_pauseStamp;

        if (dStopOffset > 0)

        {

          if (dStopOffset <= dSeek)

          {

            RTMP_LogPrintf("Already Completed\n");

            nStatus = RD_SUCCESS;

            break;

          }

        }

        if (!RTMP_ReconnectStream(&rtmp, dSeek))

        {

          RTMP_Log(RTMP_LOGERROR, "Failed to resume the stream\n\n");

          if (!RTMP_IsTimedout(&rtmp))

            nStatus = RD_FAILED;

          else

            nStatus = RD_INCOMPLETE;

          break;

        }

      }

      else if (!RTMP_ToggleStream(&rtmp))

      {

        RTMP_Log(RTMP_LOGERROR, "Failed to resume the stream\n\n");

        if (!RTMP_IsTimedout(&rtmp))

          nStatus = RD_FAILED;

        else

          nStatus = RD_INCOMPLETE;

          break;

      }

      bResume = TRUE;

    }

    //-----------------



    //-----------------

    rtmp.dlg->AppendCInfo("开始将媒体数据写入文件");

    //-----------------

    //下载,写入文件

    nStatus = Download(&rtmp, file, dSeek, dStopOffset, duration, bResume,

                       metaHeader, nMetaHeaderSize, initialFrame,

                       initialFrameType, nInitialFrameSize,

                       nSkipKeyFrames, bStdoutMode, bLiveStream, bHashes,

                       bOverrideBufferTime, bufferTime, &percent);

    free(initialFrame);

    initialFrame = NULL;





    /* If we succeeded, we're done.*/

    if (nStatus != RD_INCOMPLETE || !RTMP_IsTimedout(&rtmp) || bLiveStream)

        break;

  }





  //当下载完的时候

  if (nStatus == RD_SUCCESS)

  {

    //-----------------

    rtmp.dlg->AppendCInfo("写入文件完成");

    //-----------------

    RTMP_LogPrintf("Download complete\n");

  }

  //没下载完的时候

  else if (nStatus == RD_INCOMPLETE)

  {

    //-----------------

    rtmp.dlg->AppendCInfo("写入文件可能不完整");

    //-----------------

    RTMP_LogPrintf

      ("Download may be incomplete (downloaded about %.2f%%), try resuming\n",percent);

  }

  //后续清理工作

clean:

  //-----------------

  rtmp.dlg->AppendCInfo("关闭连接");

  //-----------------

  RTMP_Log(RTMP_LOGDEBUG, "Closing connection.\n");

  RTMP_Close(&rtmp);

  rtmp.dlg->AppendCInfo("关闭文件");

  if (file != 0)

    fclose(file);

  rtmp.dlg->AppendCInfo("关闭Socket");

  CleanupSockets();





#ifdef _DEBUG

  if (netstackdump != 0)

    fclose(netstackdump);

  if (netstackdump_read != 0)

    fclose(netstackdump_read);

#endif

  return nStatus;

}









其中InitSocket()代码很简单,初始化了Socket,如下:





// 初始化 sockets

int InitSockets()

{

#ifdef WIN32

  WORD version;

  WSADATA wsaData;





  version = MAKEWORD(1, 1);

  return (WSAStartup(version, &wsaData) == 0);

#else

  return TRUE;

#endif

}





CleanupSockets()则更简单:





inline void CleanupSockets()

{

#ifdef WIN32

  WSACleanup();

#endif

}





Download()函数则比较复杂:





int  Download(RTMP * rtmp, // connected RTMP object

FILE * file, uint32_t dSeek, uint32_t dStopOffset, double duration, int bResume, char *metaHeader, 

         uint32_t nMetaHeaderSize, char *initialFrame, int initialFrameType, uint32_t nInitialFrameSize, 

         int nSkipKeyFrames, int bStdoutMode, int bLiveStream, int bHashes, int bOverrideBufferTime, 

         uint32_t bufferTime, double *percent) // percentage downloaded [out]

{

  int32_t now, lastUpdate;

  int bufferSize = 64 * 1024;

  char *buffer = (char *) malloc(bufferSize);

  int nRead = 0;





  //long ftell(FILE *stream);

  //返回当前文件指针

  RTMP_LogPrintf("开始下载!\n");

  off_t size = ftello(file);

  unsigned long lastPercent = 0;

  //时间戳

  rtmp->m_read.timestamp = dSeek;





  *percent = 0.0;





  if (rtmp->m_read.timestamp)

  {

    RTMP_Log(RTMP_LOGDEBUG, "Continuing at TS: %d ms\n", rtmp->m_read.timestamp);

  }

  //是直播

  if (bLiveStream)

  {

    RTMP_LogPrintf("直播流\n");

  }

  else

  {

      // print initial status

      // Workaround to exit with 0 if the file is fully (> 99.9%) downloaded

      if (duration > 0)

      {

        if ((double) rtmp->m_read.timestamp >= (double) duration * 999.0)

        {

          RTMP_LogPrintf("Already Completed at: %.3f sec Duration=%.3f sec\n",

(double) rtmp->m_read.timestamp / 1000.0,

(double) duration / 1000.0);

          return RD_SUCCESS;

        }

        else

        {

          *percent = ((double) rtmp->m_read.timestamp) / (duration * 1000.0) * 100.0;

          *percent = ((double) (int) (*percent * 10.0)) / 10.0;

          RTMP_LogPrintf("%s download at: %.3f kB / %.3f sec (%.1f%%)\n",

                  bResume ? "Resuming" : "Starting",

                  (double) size / 1024.0, (double) rtmp->m_read.timestamp / 1000.0,

                  *percent);

        }

      }

      else

      {

        RTMP_LogPrintf("%s download at: %.3f kB\n",

          bResume ? "Resuming" : "Starting", (double) size / 1024.0);

      }

  }





  if (dStopOffset > 0)

    RTMP_LogPrintf("For duration: %.3f sec\n", (double) (dStopOffset - dSeek) / 1000.0);





  //各种设置参数到rtmp连接

  if (bResume && nInitialFrameSize > 0)

  rtmp->m_read.flags |= RTMP_READ_RESUME;

  rtmp->m_read.initialFrameType = initialFrameType;

  rtmp->m_read.nResumeTS = dSeek;

  rtmp->m_read.metaHeader = metaHeader;

  rtmp->m_read.initialFrame = initialFrame;

  rtmp->m_read.nMetaHeaderSize = nMetaHeaderSize;

  rtmp->m_read.nInitialFrameSize = nInitialFrameSize;





  now = RTMP_GetTime();

  lastUpdate = now - 1000;

  do{

      //从rtmp中把bufferSize(64k)个数据读入buffer

      nRead = RTMP_Read(rtmp, buffer, bufferSize);

      //RTMP_LogPrintf("nRead: %d\n", nRead);

      if (nRead > 0)

{

//函数:size_t fwrite(const void* buffer,size_t size,size_t count,FILE* stream);

//向文件读入写入一个数据块。返回值:返回实际写入的数据块数目

//(1)buffer:是一个指针,对fwrite来说,是要输出数据的地址。

//(2)size:要写入内容的单字节数;   

//(3)count:要进行写入size字节的数据项的个数;   

//(4)stream:目标文件指针。   

//(5)返回实际写入的数据项个数count。

//关键。把buffer里面的数据写成文件

       if (fwrite(buffer, sizeof(unsigned char), nRead, file) != (size_t) nRead)

       {

 RTMP_Log(RTMP_LOGERROR, "%s: Failed writing, exiting!", __FUNCTION__);

 free(buffer);

 return RD_FAILED;

       }





       //记录已经写入的字节数

       size += nRead;





       //RTMP_LogPrintf("write %dbytes (%.1f kB)\n", nRead, nRead/1024.0);

       if (duration <= 0) // if duration unknown try to get it from the stream (onMetaData)

duration = RTMP_GetDuration(rtmp);





       if (duration > 0)

       {

// make sure we claim to have enough buffer time!

if (!bOverrideBufferTime && bufferTime < (duration * 1000.0))

         {

           bufferTime = (uint32_t) (duration * 1000.0) + 5000; // 再加5s以确保buffertime足够长





           RTMP_Log(RTMP_LOGDEBUG,

             "Detected that buffer time is less than duration, resetting to: %dms",

             bufferTime);

           //重设Buffer长度

           RTMP_SetBufferMS(rtmp, bufferTime);

           //给服务器发送UserControl消息通知Buffer改变

           RTMP_UpdateBufferMS(rtmp);

         }





         //计算百分比

         *percent = ((double) rtmp->m_read.timestamp) / (duration * 1000.0) * 100.0;

         *percent = ((double) (int) (*percent * 10.0)) / 10.0;

         if (bHashes)

         {

           if (lastPercent + 1 <= *percent)

           {

             RTMP_LogStatus("#");

             lastPercent = (unsigned long) *percent;

           }

         }

         else

         {

           //设置显示数据的更新间隔200ms

           now = RTMP_GetTime();

           if (abs(now - lastUpdate) > 200)

           {

             RTMP_LogStatus("\r%.3f kB / %.2f sec (%.1f%%)",

               (double) size / 1024.0,

               (double) (rtmp->m_read.timestamp) / 1000.0, *percent);

               lastUpdate = now;

           }

         }

       }

       else

       {

         //现在距离开机的毫秒数

         now = RTMP_GetTime();

         //每间隔200ms刷新一次数据

         if (abs(now - lastUpdate) > 200)

         {

           if (bHashes)

             RTMP_LogStatus("#");

           else

             //size为已写入文件的字节数

             RTMP_LogStatus("\r%.3f kB / %.2f sec", (double) size / 1024.0,

     (double) (rtmp->m_read.timestamp) / 1000.0);

             lastUpdate = now;

         }

       }

     }

#ifdef _DEBUG

      else

{

 RTMP_Log(RTMP_LOGDEBUG, "zero read!");

}

#endif





  } while (!RTMP_ctrlC && nRead > -1 && RTMP_IsConnected(rtmp) && !RTMP_IsTimedout(rtmp));

  

  free(buffer);

  if (nRead < 0)  //nRead是读取情况

    nRead = rtmp->m_read.status;





  /* Final status update */

  if (!bHashes)

  {

      if (duration > 0)

      {

 *percent = ((double) rtmp->m_read.timestamp) / (duration * 1000.0) * 100.0;

 *percent = ((double) (int) (*percent * 10.0)) / 10.0;

 //输出

 RTMP_LogStatus("\r%.3f kB / %.2f sec (%.1f%%)",

   (double) size / 1024.0,

   (double) (rtmp->m_read.timestamp) / 1000.0, *percent);

      }

      else

      {

 RTMP_LogStatus("\r%.3f kB / %.2f sec", (double) size / 1024.0,

   (double) (rtmp->m_read.timestamp) / 1000.0);

      }

  }





  RTMP_Log(RTMP_LOGDEBUG, "RTMP_Read returned: %d", nRead);

  //读取错误

  if (bResume && nRead == -2)

  {

      RTMP_LogPrintf("Couldn't resume FLV file, try --skip %d\n\n",

nSkipKeyFrames + 1);

      return RD_FAILED;

  }

  //读取正确

  if (nRead == -3)

    return RD_SUCCESS;

  //没读完...

  if ((duration > 0 && *percent < 99.9) || RTMP_ctrlC || nRead < 0

      || RTMP_IsTimedout(rtmp))

  {

      return RD_INCOMPLETE;

  }





  return RD_SUCCESS;

}









以上内容是我能理解到的rtmpdump.c里面的内容。





原文链接:

http://blog.csdn.net/leixiaohua1020/article/details/12952977

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