I'm using an motion triggered camera which produces an MP4 file for each event. I would like join selected events inserting some visual or audible notification that it's a new scene. I found a short MP4 bleeper but, seemingly, it is not compatible with MP4s from the camera because it reports that the bleeper MP4 needs re-encoding which I don't know how to do. I know that MP4joiner is delightfully uncomplicated but I think it would be beneficial to have the option of adding scene dividers.