关于MCI控制的十万个为什么之一，希望渺茫还是期待高手现身

[shu]

以下是我用到的打开、播放、定位程序：
open:
//Open the device
MCI_DGV_OPEN_PARMS OpenParms;
OpenParms.lpstrDeviceType="MPEGVideo2";
OpenParms.lpstrElementName=(LPSTR) Filename.GetBuffer(0);
OpenParms.wDeviceID=NULL;
OpenParms.hWndParent=pWnd->m_hWnd;
OpenParms.dwStyle=WS_CHILD|WS_VISIBLE;
if (mciSendCommand (NULL,MCI_OPEN, (DWORD)(MCI_OPEN_ELEMENT|MCI_DGV_OPEN_PARENT),(DWORD)(LPVOID)&OpenParms))
return FALSE;
m_wDeviceID=OpenParms.wDeviceID;
m_bOpned=TRUE;

//Set the format to frames
MCI_DGV_SET_PARMS SetParms;
SetParms.dwTimeFormat=MCI_FORMAT_MILLISECONDS;//FRAMES;
if (mciSendCommand (m_wDeviceID,MCI_SET,MCI_SET_TIME_FORMAT,(DWORD) (LPVOID)&SetParms))
{
close ();
return FALSE;
}
//Seek to the beginning of the JuneAVIVideo
mciSendCommand (m_wDeviceID,MCI_SEEK,MCI_SEEK_TO_START,NULL);


play:

PlayParms.dwCallback=(DWORD)hParent;//可以为空此时在任意窗口中播放
PlayParms.dwFrom=GetCurrentFrame();
DWORD dwFlags=MCI_FROM|MCI_MCIAVI_PLAY_WINDOW ;
if (mciSendCommand (m_wDeviceID,MCI_PLAY,dwFlags,(DWORD)(LPVOID)&PlayParms))
return FALSE;

Seek:

MCI_SEEK_PARMS SeekParms;
SeekParms.dwTo = nFrame;
if (mciSendCommand (m_wDeviceID,MCI_SEEK,MCI_TO | MCI_WAIT,(DWORD)(LPVOID) &SeekParms))
return FALSE;


问题是有的MPEG4 AVI能正常播放和SEEK，但个别的不能SEEK，SEEK后就不出声了！
请帮忙看看，到底怎么回事？

[Hanzo]

不会,up

[司马青衫依旧]

我一直很想知道有关MCI的详细讲解！
up

[shu]

强制结帖！
无奈！