Controlling video playback
--------------------------
-TODO
+Themes have some programmatic control over video playback. In particular,
+if you want to make a video start from the beginning, you can do::
+
+ video:rewind()
+
+which will instantly make it start from the first frame again. This can be
+useful if you e.g. want the video to start when you're switching to it,
+or if you're not really using it to loop (e.g. as a transition marker).
+
+You can also change its rate, e.g. by::
+
+ video:change_rate(2.0)
+
+This will make it play at twice its usual speed. Your rate should not be
+negative nor exactly zero. Be aware that once you've set a rate, the player
+will wait for the next frame before considering any other commands,
+so if you set your rate to e.g. 0.001 to nearly stop it, you will indeed
+need to wait 16.67 seconds (assuming 60 fps video) before you can speed it
+up again. This restriction may be lifted in the future.
+
Integration with CasparCG
-------------------------