public static extern Int32 VdaSdk_PlayBackByTaskUnit(ref TVDASDK_TASK_UNIT_VOD_INFO ptVodInfoByTaskUnit, TfuncPlayPosCB pfuncPlayPos, UInt32 dwUserData);
public static extern UInt32 RvodSdk_PlayBackVideo(ref TRVODSDK_PLAYBACK_VOD_INFO ptVodInfo, TfuncPlayPosCB pfuncPlayPos, UInt32 dwUserData);