Why videowriter produces nothing?(no video, no error)

edit

`VideoWriter video;
 video.open("video.mp4",
                0x21,
                camera_fps,
                Size(frame.cols, frame.rows));
 video.write(frame);//it's some cycle here
 video.release();`

This code produces no output(no file, no log) but if i switch file name to "video.avi" and codec to CV_FOURCC('D','I','V','3'), there are .avi video. So why this program doesn't create an mp4 file and also doesn't report any error?