RTMP推送延时测试

为什么需要ChangeChunkSize这个函数，RTMP需要通过这个包指定一个ChunkSize？？

pack.m_body[3] = nChunkSize & 0xff; //大字节序
pack.m_body[2] = nChunkSize >> 8;
pack.m_body[1] = nChunkSize >> 16;
pack.m_body[0] = nChunkSize >> 24;

m_pRtmp->m_outChunkSize = nChunkSize;

SendPacket(unsigned int nPacketType, unsigned int nHeaderType,char *data, unsigned int size, unsigned int nTimestamp)函数调用了

int nRet = RTMP_SendPacket(m_pRtmp, &packet, TRUE);

connect函数中调用：

RTMP_SetupStream(m_pRtmp, nprotocol, &av_host, nport, &av_sockhost, &av_playpath, &av_tcUrl, 0, 0, 
        &av_app, 0, 0, 0, 0, 0, 0, 0, 0, 1, 5);

RTMP_EnableWrite(m_pRtmp);
if (!RTMP_Connect(m_pRtmp, NULL))
if (!RTMP_ConnectStream(m_pRtmp, 0))

int CVideoDecoder::DecodeSps(unsigned char* pData, int nSize)处理spspps，有一个数据成员szSpsPpsNal用于保存处理结果：

unsigned char* szSpsPpsNal;

int CVideoDecoder::DecodeFrame(unsigned char* pData, int nSize, size_t nTimeStamp, video_type eType)

int nRet = avcodec_decode_video2(m_pCodecCtx, m_pFrame, &got_picture, &m_packet);

if (got_picture)
{
   ProcessPicture(m_nImgWidth, m_nImgHeight, m_pFrame, nTimeStamp);
　　……
}

int CVideoDecoder::Decode(unsigned char* pData, int nSize, size_t nTimeStamp)解码函数:

if (zCodeId == 7)
    {
        char zFrameType = *pData++ >> 4;
        // 1:Iframe  7:AVC  关键帧
        if (zFrameType == 1)
        {
            // IFrame, also key frame
            unsigned char zAVCFrameType = *pData++;
            //sps、pps数据
            if (zAVCFrameType == 0)
            {
                return DecodeSps(pData, nSize - 2);
            }
            else if (zAVCFrameType == 1)//关键帧视频数据
            {
                return DecodeFrame(pData, nSize - 2, nTimeStamp, TYPE_IDR);
            }
            else if (zAVCFrameType == 2)
            {
                LOG("[%d] 2 = AVC end of sequence
", GetTickCount());
            }
        }
        else if (zFrameType == 2)// 2:Pframe  7:AVC  
        {
//            LOG("[%d] get P frame..
", GetTickCount());
            // P frame 
            pData++; // should always be 1;
            return DecodeFrame(pData, nSize - 2, nTimeStamp, TYPE_P);
        }
        else
        {
            LOG("[%d] Unsupported frame type: %d
", GetTickCount(), zFrameType);
            return -1;
        }
    }
    else
    {
        LOG("[%d] Unsupported video type: %d
", GetTickCount(), zCodeId);
        return -1;
    }

int CVideoService::ConnectRTMP(const string& strRtmpUrl)

m_Rtmp = srs_rtmp_create(strRtmpUrl.c_str());
if ((ret = srs_rtmp_handshake(m_Rtmp)) != 0)
if ((ret = srs_rtmp_connect_app(m_Rtmp)) != 0)
if ((ret = srs_rtmp_play_stream(m_Rtmp)) != 0)

DWORD GetTickCount(void); GetTickCount返回（retrieve）从操作系统启动所经过（elapsed）的毫秒数。

enum的这个用法：

enum 
{
    CHANGE_NONE,
    CHANGE_INCREASE,
    CHANGE_DECREASE
}m_eCurrentChangeState;

int CVideoService::VideoProcessThreadImpl(void)

if ((nret = srs_rtmp_read_packet(m_Rtmp, &type, &timestamp, &data, &size)) == 0)//其中的data为char*，并未分配空间，因此可能在这个函数内有内存分配操作

除了ProcessPicture外，还会调用很多的CEventNotifier::GetEventNotifier().NotifyEvent及NotifyEventSync ：

if (got_picture){
     bNeedShowMessage = true;
     ProcessPicture(nImgWidth, nImgHeight, m_pFrame, nTimeStamp);
     //printf("%d: IFrame decode OK, return; %d, nal len: %d
", nTimeStamp, nRet, nNalLen); 
}

CEventNotifier::GetEventNotifier().NotifyEvent(pService->m_strDeviceCode, EVENT_VIDEO_REPLAYING, 0);
CEventNotifier::GetEventNotifier().NotifyEvent(m_strDeviceCode, EVENT_VIDEO_BAND_WIDTH_LOW);
CEventNotifier::GetEventNotifier().NotifyEventSync(m_strDeviceCode, EVENT_VIDEO_UPDATE_INFO_W_H, (WPARAM)nImgWidth, (LPARAM)nImgHeight);

类CVideoService有一个成员变量volatile bool m_bPlaying;但是它好像只在函数int CVideoService::CancelVideoProcess()里被改变。

如果没有定义#ifdef USE_SRS_LIBRTMP ，才会在int CVideoService::VideoProcessThreadImpl(void)函数内

用到CVideoService类的成员变量CVideoDecoder m_pVideoDecoder来进行视频处理解码。其中CVideoDecoder类中包含：

class CVideoDecoder
{
        ……
private:
    AVCodecContext  *m_pCodecCtx;
    AVFrame         *m_pFrame;
    AVPacket m_packet;
    unsigned char* szSpsPpsNal;
    size_t nSpsPpsLen;
    bool m_bFirstFrame;
    int m_nImgWidth;
    int m_nImgHeight;
    string m_strDeviceCode;
};

昨天在想GetDownloadSpeedOnTimer这个函数是怎么定时检测调整速度的，原来是在VideoProcessThreadImpl函数内有：

CGlobalTimerManager::GetTimerManager().SetTimer(TIMER_DOWNLOAD_SPEED_DETECTED, 5 * 1000, CVideoService::GetDownloadSpeedOnTimer, this);

#else
int CVideoService::VideoProcessThreadImpl(void)函数内有计算延时的：

LOG("delay time : %d
", GetTickCount() - rPacket.m_nTimeStamp - CControlInfoManage::GetControlInfoManager().GetDiffTime(m_strDeviceCode));

但是在另一个VideoProcessThreadImpl函数内却没有，此外

while (RTMP_IsConnected(m_Rtmp) && RTMP_ReadPacket(m_Rtmp, &rPacket))

前一个用的是srs_rtmp_read_packet。

int CVideoService::ProcessInvokeMessage(RTMPPacket *rPacket)这个函数似乎也是在没有定义#ifdef USE_SRS_LIBRTMP 的时候才定义的。具体作用是什么？？

#ifndef USE_SRS_LIBRTMP
    int ProcessInvokeMessage(RTMPPacket *packet);
#endif

RTMP_CONNECT_RESULT CRTMPStream::Connect(const char* szBaseUrl, const char* szSessionId, const char* szPadCode, const char* szstreamName, const char* strPublishCode)

RTMP_SetupStream(m_pRtmp, nprotocol, &av_host, nport, &av_sockhost, &av_playpath, &av_tcUrl, 0, 0, 
        &av_app, 0, 0, 0, 0, 0, 0, 0, 0, 1, 5);

CGlobalTimerManager::GetTimerManager()的setTimer和killTimer函数用到参数TIMER_DOWNLOAD_SPEED_DETECTED（一个宏），难道它里面有一个关联容器对各个定时器进行关联？？