Transport controls
The five playback buttons on the phone, what each one runs on the host, and why the keyboard fallback needs the Adobe app in the foreground.
The bar at the bottom of the live view drives playback on the host. Each press sends one message over the control channel; the desktop plugin runs the corresponding command in Premiere Pro or After Effects.
The five buttons
Left to right:
| Button | Glyph | Sends |
|---|---|---|
| Go to In point | Bracket with a triangle pointing left | 0x25 |
| Step back one frame | Left frame arrow | 0x22 |
| Play / Pause | Play or pause symbol | 0x20 |
| Step forward one frame | Right frame arrow | 0x21 |
| Go to Out point | Bracket with a triangle pointing right | 0x26 |
The two outer glyphs are drawn to match Premiere Pro's own Go to In and Go to Out buttons — a bracket against a triangle pointing outward.
The visible glyphs are 34 points, but every button's tap target is expanded to 44 points, so a press slightly beside the icon still registers.
There are no shuttle or jog controls in the app. The wire protocol reserves
opcodes for large steps (0x23, 0x24) and for shuttle left / stop / right
(0x27–0x29), and the desktop plugin implements all of them, but the app
declares only the five cases above — no shipping build can send a shuttle
command to any host. Anything that describes shuttle as a button you can press
is describing the protocol, not the product.
What each button runs on the host
The plugin tries two routes in order, per press.
Route 1 — the Control Surface plugin (Premiere Pro)
PremiereLiveCtrl is a sibling plugin that talks to Premiere Pro's real transport and command APIs. When it is loaded and connected, presses become genuine Premiere Pro commands:
| Button | Premiere Pro command |
|---|---|
| Go to In point | Go to In |
| Step back | Step Back |
| Play / Pause | Platform-specific — see below |
| Step forward | Step Forward |
| Go to Out point | Go to Out |
This route works regardless of your custom keyboard shortcuts, because it invokes the commands by identity rather than by simulating a key.
Play and pause are the awkward pair. Every SDK play call silently does nothing while Premiere Pro is backgrounded — it returns success with no playback, because the playback manager cannot resolve a target panel without OS focus. So the bridge routes around it, differently on each platform:
- Windows — pause runs the Program Monitor's play/stop toggle command. Play posts a Space keystroke directly to Premiere Pro's panel window, which bypasses the OS foreground check entirely, preceded by a synthetic activation and followed by a re-check-and-retry about 250 ms later in case the app was still waking up.
- macOS — pause runs the global shuttle-stop command (the K shortcut's own primitive). Play runs shuttle-right at its first speed step, which is exactly the L key: forward playback at 1× until you pause. Neither is foreground-gated.
Both of these work with the Adobe app in the background. That is the whole reason the Control Surface plugin exists.
Preferences → Control Surface lists this device as PremiereLive, not PreviewMonitor. That display string was never renamed. The Mercury Transmit device is correctly named PreviewMonitor. See Transport control for the install path.
Route 2 — synthetic keystrokes (fallback)
If the Control Surface plugin is not installed, has not connected, or returns an error for a given press, the plugin falls back to posting a keystroke:
| Button | Keystroke |
|---|---|
| Go to In point | Shift+I |
| Step back | ← |
| Play / Pause | Space |
| Step forward | → |
| Go to Out point | Shift+O |
The keyboard fallback only works while the Adobe app is the foreground application. Synthetic keystrokes go to whatever window has focus. If Premiere Pro is minimized, behind your browser, or the desktop Setup window has focus, the presses land somewhere else and the phone appears dead.
This is also why the fallback can quietly do the wrong thing: Shift+I and the arrow keys mean something different in another app. Install the Control Surface plugin and the fallback stops being needed.
If a press does nothing, see Transport does nothing.
After Effects
After Effects gets its transport from a separate bridge, PremiereLiveAE.aex, which uses the AEGP API against the front composition.
| Button | After Effects behavior |
|---|---|
| Go to In point | Moves the composition's current-time indicator to its start |
| Step back one frame | Moves the CTI back one frame |
| Play / Pause | Taps Space — After Effects' RAM-preview toggle |
| Step forward one frame | Moves the CTI forward one frame |
| Go to Out point | Moves the CTI to the composition's end |
Frame stepping and the two go-to buttons use the real API, so they move the time indicator directly and cannot nudge a selected layer the way an arrow keystroke would. Note the outer two buttons behave differently here than in Premiere Pro: the bridge has no in/out marks to honor, so it seeks to the composition's start and its last whole frame.
PremiereLiveAE.aex ships in no installer. Neither the Windows installer nor the MSI includes it, and it is not built for macOS at all — so unless you have placed it by hand on Windows, the table above does not describe your machine. Every press falls through to synthetic keystrokes instead, which on Windows go through SendInput and therefore require After Effects to be the foreground application. On macOS the fallback posts events into After Effects' own queue, so the foreground barrier is different there.
With the bridge installed, none of the five buttons needs After Effects in front — including play/pause, which posts Space straight to After Effects' panel window and first flips the application's active flag, so it lands even when After Effects is minimized.
Video works everywhere: it comes from the same shared Transmit plugin, so the live picture behaves identically to Premiere Pro. It is only transport that is reduced.
Without the bridge, the step buttons edit your composition. The keystroke fallback sends → and ←, which in After Effects nudge the selected layer in time rather than moving the playhead. The picture on the phone does not change, so nothing tells you it happened. Deselect all layers before using the phone's transport in After Effects, or install the bridge.
After Effects has no audio path at all. The plugin's After Effects side handles no audio, and the speaker button on the phone never turns orange there — it looks like a working mute toggle and delivers permanent silence. See No audio.
See After Effects artist for the practical workflow.
The play/pause glyph
The glyph flips the instant you tap it, before the host has answered. That is deliberate — a transport button that waits a network round-trip to change state feels broken.
The plugin then sends its own authoritative playback-state message on every real timeline transition, whatever caused it: your tap, Space pressed in Premiere Pro, a menu command, a shuttle stop. When that arrives, the optimistic flip is dropped and the glyph follows the host.
Two consequences worth knowing:
- Pressing Space at the keyboard updates the phone. The glyph is not driven by your taps alone.
- A frame step never moves the glyph. Stepping does not start Premiere Pro's playback clock, so no state edge is emitted and there is nothing to reconcile.
The optimistic state is held by the app rather than by the view, so it survives the HUD auto-hiding and coming back.
If the host is running a plugin too old to report play state, the button falls back to a plain local toggle.
Position in a platform layout
With a TikTok, Reels, or Shorts layout active, the mock tab bar covers the bottom of the screen. The transport bar lifts above it automatically so the two never fight for the same pixels. In Standard and Full Screen it sits on the normal safe-area baseline.
Local clips
Preview from Photos or Files has its own transport bar with the same five positions plus a scrub slider. There the outer buttons are Go to start and Go to end rather than In and Out points — a local file has no in/out marks.
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The live view
Gestures, the HUD button row, Stay on vs Auto-hide chrome, orientation behavior, and what the waiting and transmit-paused states mean.
Layouts and safe zones
All twelve layout modes, the Universal Safe Zone with its opacity and color controls, the caption editor, and when the picture fills versus letterboxes.