RTMPDump原始碼分析-main函式(1)
阿新 • • 發佈：2019-01-22
RTMPDump.c原始碼中的main函式主要是：
InitSockets();//初始化Socket
RTMP_Init();//初始化結構體
RTMP_ParseURL();//解析輸入URL
RTMP_SetupStream();//一些設定
fopen();//開啟檔案，準備寫入
RTMP_Connect();//建立NetConnection
RTMP_ConnectStream()//建立NetStream
Download();//下載函式
RTMP_Close();//關閉連線
fclose();//關閉檔案
CleanupSockets();//清理Socket1. InitiSocket和 CleanupSocket對於Linux來說什麼也沒有做
// starts sockets int InitSockets() { #ifdef WIN32 WORD version; WSADATA wsaData; version = MAKEWORD(1, 1); return (WSAStartup(version, &wsaData) == 0); #else return TRUE; #endif } inline void CleanupSockets() { #ifdef WIN32 WSACleanup(); #endif }
2. Download函式
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 bRealtimeStream, int bHashes, int bOverrideBufferTime, uint32_t bufferTime, double *percent) // percentage downloaded [out] { int32_t now, lastUpdate; int bufferSize = 64 * 1024; char *buffer; int nRead = 0; // 返回當前檔案指標 off_t size = ftello(file); unsigned long lastPercent = 0; // 需要讀取的時間戳 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); } // 是否是直播流 if (bLiveStream) { RTMP_LogPrintf("Starting Live Stream\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 (bRealtimeStream) RTMP_LogPrintf(" in approximately realtime (disabled BUFX speedup hack)\n"); } if (dStopOffset > 0) RTMP_LogPrintf("For duration: %.3f sec\n", (double) (dStopOffset - dSeek) / 1000.0); // 設定RTMP連線引數 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; buffer = (char *) malloc(bufferSize); now = RTMP_GetTime(); lastUpdate = now - 1000; do { //從rtmp中把bufferSize（64k）個數據讀入buffer nRead = RTMP_Read(rtmp, buffer, bufferSize); //RTMP_LogPrintf("nRead: %d\n", nRead); if (nRead > 0) { //函式：size_t fwrite(const void* buffer,size_t size,size_t count,FILE* stream); //向檔案讀入寫入一個數據塊。返回值：返回實際寫入的資料塊數目 //（1）buffer：是一個指標，對fwrite來說，是要輸出資料的地址。 //（2）size：要寫入內容的單位元組數； //（3）count:要進行寫入size位元組的資料項的個數； //（4）stream:目標檔案指標。 //（5）返回實際寫入的資料項個數count。 //關鍵。把buffer裡面的資料寫成檔案 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; } // 記錄寫入位元組數 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)) { // 再加5s以確保buffertime足夠長 bufferTime = (uint32_t) (duration * 1000.0) + 5000; // extra 5sec to make sure we've got enough RTMP_Log(RTMP_LOGDEBUG, "Detected that buffer time is less than duration, resetting to: %dms", bufferTime); // 重設Buffer長度 RTMP_SetBufferMS(rtmp, bufferTime); // 給伺服器傳送UserControl訊息通知Buffer改變 RTMP_UpdateBufferMS(rtmp); } // 計算百分比 *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 { // 設定顯示資料的更新間隔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 { // 現在距離開機的毫秒數 now = RTMP_GetTime(); // 每間隔200ms重新整理一次資料 if (abs(now - lastUpdate) > 200) { // size為已寫入檔案的位元組數 if (bHashes) RTMP_LogStatus("#"); else RTMP_LogStatus("\r%.3f kB / %.2f sec", (double) size / 1024.0, (double) (rtmp->m_read.timestamp) / 1000.0); lastUpdate = now; } } } else { #ifdef _DEBUG RTMP_Log(RTMP_LOGDEBUG, "zero read!"); #endif if (rtmp->m_read.status == RTMP_READ_EOF) break; } } while (!RTMP_ctrlC && nRead > -1 && RTMP_IsConnected(rtmp) && !RTMP_IsTimedout(rtmp)); free(buffer); if (nRead < 0) 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; 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); if (bResume && nRead == -2) { RTMP_LogPrintf("Couldn't resume FLV file, try --skip %d\n\n", nSkipKeyFrames + 1); return RD_FAILED; } if (nRead == -3) return RD_SUCCESS; if ((duration > 0 && *percent < 99.9) || RTMP_ctrlC || nRead < 0 || RTMP_IsTimedout(rtmp)) { return RD_INCOMPLETE; } return RD_SUCCESS; }
3. main函式
int main(int argc, char **argv) { ... // 最先執行開始檢查引數裡面是否有退出 // Check for --quiet option before printing any output int index = 0; while (index < argc) { if (strcmp(argv[index], "--quiet") == 0 || strcmp(argv[index], "-q") == 0) RTMP_debuglevel = RTMP_LOGCRIT; index++; } RTMP_LogPrintf("RTMPDump %s\n", RTMPDUMP_VERSION); RTMP_LogPrintf ("(c) 2010 Andrej Stepanchuk, Howard Chu, The Flvstreamer Team; license: GPL\n"); if (!InitSockets()) { RTMP_Log(RTMP_LOGERROR, "Couldn't load sockets support on your platform, exiting!"); return RD_FAILED; } /* sleep(30); */ RTMP_Init(&rtmp); ... // 檢查命令列引數 while ((opt = getopt_long(argc, argv, "hVveqzRr:s:t:i:p:a:b:f:o:u:C:n:c:l:y:Ym:k:d:A:B:T:w:x:W:X:S:#j:", longopts, NULL)) != -1) { ... } ... if (!fullUrl.av_len) { RTMP_SetupStream(&rtmp, protocol, &hostname, port, &sockshost, &playpath, &tcUrl, &swfUrl, &pageUrl, &app, &auth, &swfHash, swfSize, &flashVer, &subscribepath, &usherToken, dSeek, dStopOffset, bLiveStream, timeout); } else { if (RTMP_SetupURL(&rtmp, fullUrl.av_val) == FALSE) { RTMP_Log(RTMP_LOGERROR, "Couldn't parse URL: %s", fullUrl.av_val); return RD_FAILED; } } ... // 找到最後的關鍵幀 // ok, we have to get the timestamp of the last keyframe (only keyframes are seekable) / last audio frame (audio only streams) if (bResume) { 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 { 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; } } } if (!file) { if (bStdoutMode) { file = stdout; SET_BINMODE(file); } else { file = fopen(flvFile, "w+b"); if (file == 0) { RTMP_LogPrintf("Failed to open file! %s\n", flvFile); return RD_FAILED; } } } ... while (!RTMP_ctrlC) { RTMP_Log(RTMP_LOGDEBUG, "Setting buffer time to: %dms", bufferTime); RTMP_SetBufferMS(&rtmp, bufferTime); ... // 在此處下載進行 nStatus = Download(&rtmp, file, dSeek, dStopOffset, duration, bResume, metaHeader, nMetaHeaderSize, initialFrame, initialFrameType, nInitialFrameSize, nSkipKeyFrames, bStdoutMode, bLiveStream, bRealtimeStream, bHashes, bOverrideBufferTime, bufferTime, &percent); ... } ... clean: RTMP_Log(RTMP_LOGDEBUG, "Closing connection.\n"); RTMP_Close(&rtmp); if (file != 0) fclose(file); CleanupSockets(); #ifdef _DEBUG if (netstackdump != 0) fclose(netstackdump); if (netstackdump_read != 0) fclose(netstackdump_read); #endif return nStatus; }