mcisendstring重复功能不起作用

Question

运行下面的代码，视频不会重复，只是在结束时停止。它曾经工作：

    dim moviewindow as picturebox
    dim filename as string= Chr(34) & "C:\test.mp4" & Chr(34)

    mciSendString("open " & filename & " type mpegvideo alias myMovie parent " & moviewindow.Handle.ToInt32 & " style child", vbNullString, 0, IntPtr.Zero)
    mciSendString("put myMovie window at 0 0 " & moviewindow.Width & " " & moviewindow.Height, vbNullString, 0, IntPtr.Zero)
    mciSendString("setaudio myMovie volume to 0", vbNullString, 0, IntPtr.Zero)
    mciSendString("play myMovie notify repeat", vbNullString, 0, IntPtr.Zero)

在Windows 10上，AMD卡。所有图形驱动程序都是最新的。已安装LAV编解码器。

有什么想法吗？