Start downloading files
LONG NET_DVR_StartDownload( LONG lUserID, DWORD dwDownloadType, LPVOID lpInBuffer, DWORD dwInBufferSize, char const *sFileName );
[IN] Value returned by NET_DVR_Login_V40.
[IN] Downloading commands which specify the file type to download, see details in the enumeration NET_SDK_DOWNLOAD_TYPE.
[IN] Input parameters, which are different according to different downloading commands.
[IN] Input buffer size.
[IN] Path for saving downloaded files (absolute path, includes file name).
Returns -1 for failure, and returns other values as the parameters of NET_DVR_StopDownload and NET_DVR_GetDownloadState.
If returning failed, you can call NET_DVR_GetLastError to get the error code.