By describing the video, I was meaning that it worked fine for me — I saw the picture and sound.
However I just tried it again and I see the issue now. My guess is that it’s because my plugin tells the player to buffer out 15 seconds of the video before playing (in order to better get a chance of playing it all the way through smoothly). However since the video is only 11 seconds long, the player appears to freak out. Stupid thing. 🙂