Elliot,
OK, I installed a brand new version of WP 3.2.1 and the Elegance theme 1.4. I have no plugins active. The slideshow videos still didn't play, But I figured out PART of the problem. Here's what I need help with...
Problem #1
Now I can see the video and click to play. BUT there is no control bar to see how long the video is or the ability to FF or RW or see progression. Is this a limitation of the Slideshow? It seems that if YouTube provides a player with a control bar there should be one in the slideshow.
Problem #2
I'm using thumbnails instead of dots. But the slideshow gives me no image in the thumbnail for the video. Any way for me to add an image for the thumbnail of a video?
Problem #3
If you set the slideshow to "Automatic Slider Transitions", the videos will continue to rotate EVEN after the play button is pressed. So you press play, watch a few seconds and then the slider transitions to the next video. The only ways to prevent this is to hover the mouse cursor over the video to stop the transitions (which webpage visitors won't know to do) or disable the "Automatic Slider Transitions". It would make sense to stop any transitions when the video is playing AND also allow for automatic slider transitions when the videos are not playing. Is this possible to fix now or in a coming theme update?
For any of you members still having the same problem with videos not playing, this solution might help you:
Initially, I got a short URL from YouTube for each video by clicking on the "Share" button below the video, e.g. http://youtu.be/Mhj2remYgBQ. I found out these URLs will NOT work. Instead you have to put the short URL into your browser address bar and get a longer URL, e.g. http://www.youtube.com/watch?v=Mhj2remYgBQ&feature=youtu.be. Use the longer URL in the Slideshow field for "Image/Video URL". Then the video will actually show up in your slideshow. Of course, you still have to also include at least one image slide in your slideshow as well or none of the videos will show up.