视频回放播放速度控制，比较准确

对视频文件进行回放，主要是对播放时间的控制比较麻烦，通过两个相对事件比较，基本能做到播放事件的准确性。

文件两帧之间的事件 ><= 上一帧播放时间于当前时间的大小比较来实现。

void playbacksource::PlaybackFile(void* param)

{

AV_FRAME frame;

int skip_audio = 0;

int64_t
iNowSystemTicket = 0;

int64_t
iLastSystemTicket = 0;

float fSpped= 0.0;

int64_t
iLastSecondTick = 0; //Only for send current frame time to client

memset( &frame,0,sizeof(AV_FRAME) );

frame.Buffer = (char *)malloc( MAX_FRAME_SIZE );

if (frame.Buffer == NULL)

{

return ;

}

m_pGPSBuffer = (char *)malloc( MAX_GPS_MSG_LENGTH );

if (m_pGPSBuffer == NULL)

{

return ;

}

m_bNextVideoFrameReady = false;

int iFPS = 0;

DATETIME FrameTime;

while (!GetEndingState())

{

int rc = 0;

fSpped = GetSpeedValue();

Sleep(5);

int play_state = GetPlayingState();

int NextFrame = GetFrameByFrame();

//if (!GetPlayingState() && !GetFrameByFrame())

if (!play_state && !NextFrame)

{

m_bNextVideoFrameReady = false;

memset(&FrameTime,0,sizeof(DATETIME));

continue;

}

//n_now_system_time = GetTickCount();

if (!m_bNextVideoFrameReady)

{

switch(GetPlayingSpeed())

{

case PLAY_SPEED_X16:

rc = YMHX_RECORDFILE_GetNextKeyFrame(&m_SRF,&frame);

break;

case PLAY_SPEED_X8:

rc = YMHX_RECORDFILE_GetNextKeyFrame(&m_SRF,&frame);

break;

case PLAY_SPEED_X4:

rc = YMHX_RECORDFILE_GetNextFrame(&m_SRF,&frame);

skip_audio = 1;

break;

case PLAY_SPEED_X2:

rc = YMHX_RECORDFILE_GetNextFrame(&m_SRF,&frame);

skip_audio = 1;

break;

case PLAY_SPEED_X1:

rc = YMHX_RECORDFILE_GetNextFrame(&m_SRF,&frame);

skip_audio = 0;

break;

case PLAY_SPEED_X1_2:

rc = YMHX_RECORDFILE_GetNextFrame(&m_SRF,&frame);

skip_audio = 1;

break;

case PLAY_SPEED_X1_4:

rc = YMHX_RECORDFILE_GetNextFrame(&m_SRF,&frame);

skip_audio = 1;

break;

case PLAY_SPEED_X1_8:

rc = YMHX_RECORDFILE_GetNextFrame(&m_SRF,&frame);

skip_audio = 1;

break;

case PLAY_SPEED_X1_16:

rc = YMHX_RECORDFILE_GetNextFrame(&m_SRF,&frame);

skip_audio = 1;

break;

default:

break;

}

if (rc == 1)

{

m_bNextVideoFrameReady = 1;

OutputStream(&frame);

}

if( 0 == rc)

{

m_bPlaying = 0;

m_bNeedKeyFrame = 1;

m_bNextVideoFrameReady = 0;

if(m_pFilterAV)

m_pFilterAV->NotifyEvent(WM_GRAPHNOTIFY, EV_VIDEOEOF, NULL);

continue;

}

}//if (!m_bNextVideoFrameReady)

if (m_bNextVideoFrameReady)

{

if (frame.FrameType == A_FRAME && !skip_audio && !m_bMute)

{

CheckAudioFrameFormat(&frame);

m_pFilterAV->ProcessAudioBuffer(frame.FrameSize,frame.Buffer);

}

else if (frame.FrameType == I_FRAME || frame.FrameType == P_FRAME)

{

//Only video frame need control speed

DateTimeToMsSeconds(&m_now_frame_tick,&(frame.FrameTime));

iNowSystemTicket = GetNowMsSecondsTime();

//send frame time changed event once per second

if (iNowSystemTicket - iLastSecondTick > 1000)

{

if(m_pFilterAV)

m_pFilterAV->NotifyEvent(WM_GRAPHNOTIFY, EV_UPDATESTAMP, (LONG_PTR)(m_now_frame_tick/1000));

iLastSecondTick = iNowSystemTicket;

}

//dvr time changed

if (m_now_frame_tick < m_last_frame_tick)

{

m_last_frame_tick = m_now_frame_tick;

}

//client time changed

if (iNowSystemTicket < iLastSystemTicket)

{

iLastSystemTicket = 0;

}

//check play or not

if ( (iNowSystemTicket - iLastSystemTicket) * fSpped < m_now_frame_tick - m_last_frame_tick

&& m_now_frame_tick - m_last_frame_tick < MAX_PLAY_DELAY)

{

continue;

}

m_last_frame_tick = m_now_frame_tick;

iLastSystemTicket = iNowSystemTicket;

CheckVideoFrameFormat(&frame);

m_pFilterAV->ProcessVideoBuffer(frame.FrameSize,frame.Buffer,frame.FrameType);

//Clear frame by frame play mode

SetFrameByFrame(0);

//DBG_MSG("frame type:%d frame sequence:%u video sequence:%d\n",frame.FrameType,frame.SequenceNumber,frame.VideoSequence);

}

else if (frame.FrameType == G_FRAME && m_pGPSBuffer)

{

memcpy(m_pGPSBuffer,frame.Buffer,frame.FrameSize);

if((m_pFilterAV) &&( MAX_GPS_MSG_LENGTH > frame.FrameSize) )

m_pFilterAV->NotifyEvent(WM_GRAPHNOTIFY, EV_GPS_NOTIFY, LONG_PTR(frame.FrameSize));

}

else

{

}//if (frame.FrameType == A_FRAME) end

m_bNextVideoFrameReady = 0;

}//if (m_bNextVideoFrameReady)

}//while (!GetEndingState())

if (frame.Buffer)

free(frame.Buffer);

frame.Buffer = NULL;

if (m_pGPSBuffer)

free(m_pGPSBuffer);

m_pGPSBuffer = NULL;

}