change_rate() now works a bit more like expected.

[nageru-docs] / video.rst

diff --git a/video.rst b/video.rst
index cdef8f194674cc3343258fe2cd95ca5e73eed7b7..c41099d6e8aa2db0f4eb38d621acf35dae0c807a 100644 (file)
--- a/video.rst
+++ b/video.rst
@@ -61,11 +61,37 @@ moving the new file atomically into place, you could end up corrupting the file
 Nageru is playing from, causing it to automatically rewind before the end of
 the segment.
 
+Videos are assigned an arbitrary signal number when loaded. Whenever you need
+to refer to this signal number (say, to get its width or height for display),
+you should use *video:get_signal_num()*. Like any other signal, videos have
+a width and height, an interlaced flag (currently always false), a frame rate
+(which can vary during playback) and has_signal/is_connected member functions.
+The former is always true, but the former will be false if the video isn't
+currently playing for whatever reason (e.g., the file is corrupted, or a network
+stream is broken and hasn't reconnected yet).
+
 
 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. You can set a rate to e.g. 1e-6 if you want to
+in practice stop the video; once you change it back to normal speed,
+the next frame will resume playing.
+
 
 Integration with CasparCG
 -------------------------