+.. _speed:
+
+Controlling the playback speed
+''''''''''''''''''''''''''''''
+
+Most slow motion is at 0.5x speed (or equivalently, “2x slow motion”),
+and when you queue a clip from the clip list to the playlist, this is what
+it gets by default. However, you are free to change it to whatever you wish,
+like 0.333x, 0.25x (both are fairly common “super slow” standards) or even 1.0x.
+As long as you are reasonably close to a rational number with low integers
+(e.g. 1/2, 2/3, etc.), Futatabi will do its best to try to reuse as many
+original frames as possible, keeping quality and performance at their highest
+levels.
+
+In addition to the per-clip speed, it is often interesting to change the
+speed *during* playback of a clip. For instance, you could keep normal
+slow motion (0.5x) speed in the run-up to a shot, ramp down to 0.1x to get
+a good look at the actual shot, and then ramp back once it's done.
+When done right and not overused, this can create a dramatic effect that's
+hard to replicate using constant slowdown.
+
+To this effect, Futatabi supports a *master speed* control. It is found at
+the bottom of the window (or you can :ref:`control it using a MIDI device <midi-futatabi>`);
+note that by default, it is locked at 100% until you click the lock button
+to unlock it. (This is particularly important when using a MIDI device, where it is very easy
+to touch a slider inadvertedly, and very hard to set it back exactly at 100%.)
+The master speed control is multiplied in on top of all other speed factors,
+so if you have e.g. a clip at 0.5x and the master speed is set to 70%,
+the clip will effectively play back at 0.35x. The master speed can be set between
+10% and 200%, inclusive.
+
+Note that the master speed control governs the speed of the *output* clock,
+unlike any other speed control in Futatabi. In particular, this means that unlike
+the regular clip speeds, it affects fade times; if fade time is at 0.5 seconds
+and master speed is set to 70%, the fade will take approximately 0.714 seconds
+(0.5 divided by 0.7). It also means that the “remaining time” displays will be
+wrong if master speed is not at 100%. This is because the master speed
+is by nature unpredictable (the user can change it at any time); one cannot
+e.g. delay fades when the master speed is reduced, since turning it back up
+would mean the start of the fade were simply missed. Similarly, it is impossible
+to give a proper estimate of time remaining that takes master speed into account;
+it would be overestimating time significantly, given that the operator is likely
+to turn it back up to 100% again soon.
+
+Finally, note that when changing master speed, the speed is no longer at a
+rational, so most frames will be interpolated frames. If your GPU is not fast
+enough to interpolate every frame (ie., it is reliant on Futatabi's usual
+reuse of original frames), it will drop output frames. Normal behavior will
+resume from the next clip, when the clocks will again go in lockstep (assuming the master
+speed is at 100% at that point). If you're not ramping, or if you're done ramping,
+it's recommended to keep the speed lock on to avoid inadvertedly changing the speed.
+
+.. _coop:
+
+Working with your producer
+''''''''''''''''''''''''''
+
+Generally, we recommend that the producer (Nageru operator) and slow motion
+operator (Futatabi operator) sit closely together and can communicate verbally.
+Good cooperation between the two is essential to get a good final product;
+especially the switches to and from the replays can be a critical point.
+
+The general rule for working together is fairly obvious: The producer should
+switch to a replay when there's something to show, and switch away when there's
+nothing more to show (or, less ideally, when something live takes priority).
+Generally, when you have a playlist ready, inform your producer; they will
+count you in (three, two, one, go). At one, start playing so that you have some
+margin. If the Nageru theme is set up correctly (see :ref:`talkback`), they will
+know how much is queued up so that they can switch back before the replay runs
+out, but it doesn't hurt to give a warning up-front. The producer might also
+be able to request replays of specific events, or ask you to save something
+for later if they can't show it right now (e.g. a foul situation that wasn't called).
+
+Audio support
+'''''''''''''
+
+Since version 1.8.5, Futatabi has limited audio support. It is recorded
+(assuming Nageru is also at version 1.8.5 or newer) and saved for all inputs,
+and played back when showing a replay, but only when the replay speed is at
+100%, or very close to it. (At other speeds, you will get silence.)
+Furthermore, there is no local audio output; the Futatabi operator will not
+hear any audio, unless they use a video player into the Futatabi stream locally
+(with associated delay). All of this may change in the future.
+
+
+Replay workflows
+----------------
+
+On top of the basics outlined in :ref:`basicui`, there are many possible
+workflows; we'll discuss only two. Try out a few and see which ones fit your
+style and type of event.