The Player Window

Fusor Studio's main window is a compact strip, 384 pixels wide and 160 tall. It's frameless and floats above other windows by default, so it stays visible alongside your DJ app.

The window has three horizontal regions, top to bottom: the toolbar, the picker row, and the progress strip, plus a single-line status line along the bottom edge.

The toolbar

The top row holds icons in three groups: the gear and book on the left, the transition group in the middle, and the session group on the right.

The gear opens Settings (Ctrl+, on Windows, Cmd+, on the Mac). Click it again to close Settings. The gear is lit blue while Settings is open. The gear and its shortcut are grayed and inactive while a transition is running, so a mid-mix configuration change can't disturb it. An open Settings window closes itself the moment a transition starts, and the gear and shortcut work again once the transition ends, including after an abort. Pausing does not unlock them, and neither does reaching 100%: the lock holds through the completion wait until the transition is finalized.

If you had unsaved controller bindings open when the window closed itself, they are written to disk rather than lost, and the status line tells you so. If that profile was the active one, it is re-activated with the saved bindings.

The book opens the Library window, which stays on top beside the Fusor player. Click it again to close the Library; if the Library holds unsaved work, it asks about it first, as its own close button does. The book is lit blue while the Library is open. The Library's header switches between two sections: Fusors and Actions, each with search, sort, filter, and detail views. A Step Sets button after the section switcher opens the Step Sets window. The Library window restores the section that was open the last time it was closed.

A key icon appears to the right of the book only when the license needs attention: red when the license has stopped working, orange when a saved sign-in must be renewed, the confirm date has passed, or it falls within 7 days of that date. Hovering it shows the reason in a short line; clicking it opens Settings ▸ License. The rest of the time it is absent. While a transition is running, the key grays out to the toolbar's disabled look and the click does nothing. The tooltip adds that Settings opens after the run, and the key returns to its color once the transition ends.

The transition group (the middle) holds the controls that configure the next transition: the Run Mode switch and the two toggles. All are always visible, and disable when no fusor is loaded or when Blind Mode locks them:

• Run Mode switch (a pill with three positions). Auto (timer icon), Mixed (two overlapping circles) and Manual (hand). The lit position is blue and shows its icon, and the other two show a small dot. Each position is pressed directly. Mixed is dimmed unless the loaded fusor's mix point is Middle, or End with an effect tail. Locked to Auto in Blind Mode and in Fusor Studio Lite. See The Run Mode switch.
• Start-with-Incoming (chain link). Off by default, so you press Play to start. When on (blue), the transition auto-starts when the incoming deck begins playing. Enabling this also enables Auto Run Mode.
• Tempo Ramp (rising trend line with arrowhead). Arms a routine that changes the tempo of both decks from the outgoing track's tempo to the incoming track's tempo over the course of the transition. Dark when off, yellow when armed but not yet set up, briefly showing a spinner while setup runs, solid blue once the decks are coupled and the ramp is ready to fire.

The session group (the right) holds the always-on session controls:

• Pad Mode (grid). Toggles the 8-pad action grid in place of the picker row and progress strip. Blue when active. See Pad Mode.
• Swap (two arrows). Swaps which deck is incoming and which is outgoing. Always visible in Blind Mode; visible by default otherwise, and can be hidden via Show Manual Role Swap while Online in Settings → General. It stays visible but inactive in Pad Mode. Swap is a momentary action rather than a toggle, so it keeps a neutral dark body at all times. See Manual Role Swap.
• Pin on Top (push-pin). On by default. On the Mac the player stays over a full-screen DJ app even with Pin off. With Pin off it goes behind other windows as usual.
• Expand arrow. Opens the loaded fusor's details (Session View) and closes them when they are open. Always shown: grayed with no fusor loaded, and it does nothing during a run. It works in Pad Mode too.

On Windows, the Close button (×) sits at the far right and quits Fusor Studio. On the Mac, quit with Cmd+Q or from the app menu.

Every toggle in the toolbar turns blue when it's on. Buttons that fire an action rather than hold a state stay neutral.

The picker row

A fusor picker sits in the row, labeled with the currently loaded fusor. Clicking it opens the Library window focused on the active collection's Fusors sub-tab. Selecting a fusor there closes the Library window automatically and loads it into the Fusor player. See Loading a fusor.

A loaded fusor that's a flagged duplicate copy shows a small orange warning icon beside its name on the picker. See Authoring Overview → Where files live for how a duplicate is flagged.

If the loaded fusor has a mix point, its three-position mark sits at the right end of the picker, before the arrow. It stays bright during a run, while the rest of the picker dims. Hover it to see the mix point's name and what it means. A fusor with no mix point shows no mark.

The loaded fusor's name on the picker has a right-click menu with Unload (clear player), which drops the loaded fusor, closes the details panel and returns the player to its empty state.

The expand arrow in the toolbar opens Session View, an inline details panel between the toolbar and the picker row that shows the loaded fusor's name, the author's intent, the domains the fusor will modulate, and any actions it runs before or after the transition, laid out as a single chronological stack. Session View is also where you make session edits: quick adjustments for your own rig, saved into the fusor as you make them. See Loading a fusor: Session View for the full walkthrough.

When Pad Mode is on, the picker row is hidden and the pad grid takes its place.

The progress strip

A single horizontal strip with the progress meter as the background and a transport button at each end, with the timing readouts in the middle:

• Left: the Arm / Play / Pause button. Its behavior depends on the mode:

  • In Manual Run Mode, this button toggles between armed and unarmed. When armed, moving your DJ app's crossfader advances the transition.
  • Mixed Run Mode behaves as Auto Run Mode until the run stops at the mix point, then as Manual Run Mode.
  • In Auto Run Mode (default, press-Play), the button is the PLAY button. There is no arm step: one press starts the transition. Once running, the same button toggles between play and pause.
  • In Auto Run Mode with Start-with-Incoming on, the button is a solid dot you click to arm. The transition starts when the player receives telemetry that the incoming deck has started playing. Once running, the same button toggles between play and pause.

  See Transport Controls for the full behavior and Manual Run Mode vs Auto Run Mode for the mode distinction.

• Center: a two-column timing readout, shown in Auto and Mixed Run Mode (in Manual Run Mode the crossfader drives timing, so the readout is hidden). The left column stacks the bars stepper (< N > bars) over the incoming-deck BPM (@ NNN.N BPM); both numbers are click-to-edit. The stepper arrows step through 1, 2, 4, 8, 12, 16, 24, 32, 48 and 64 bars; from a value between two steps, an arrow goes to the nearest step in its direction. A typed value is not limited to those steps. The right column shows the time remaining (= NN.Ns) at a larger font, with a small caption under it: to end in Auto Run Mode, or to mix point in Mixed Run Mode, where the timer counts down to the mix point. The bars count always covers the whole transition. Before the transition starts it reads the time the bars and BPM produce (in Mixed Run Mode, the part of it up to the mix point); once the run is under way it counts down as progress advances, and it holds still while the run is paused. When you take over a run by hand mid-run, or a Mixed run reaches its stop, the readout disappears for the rest of that run: the crossfader is driving the timing from that point, so the bars, BPM and countdown no longer describe it. The meter and the buttons at either end stay where they are.

• Right: the Abort button, live once a transition is actually under way. It's a press-and-hold gesture rather than a click, and it terminates the transition permanently. See Transport Controls.

The progress meter itself fills from 0% to 100% as the transition progresses, and 100% is the end of the transition. The background of the meter shows a chevron pattern indicating the direction of the transition: left-deck to right-deck or right-deck to left-deck.

The mix mark and quarter marks

The loaded fusor's own mix point is the orange mix mark: a downward triangle at the top edge and an upward triangle at the bottom edge, each with a short stub toward the middle. The quarter marks are small gray triangles with no stubs, at the start, a quarter, half, three quarters and the end of the run. They are a guide when the crossfader drives progress.

Each mark is measured in the direction the meter fills, so on a right-to-left transition the 25% mark sits a quarter of the way in from the right edge. The marks at 0% and 100% are half triangles lying flat against the strip's edge. A Middle fusor's orange mark is at 50%, and a Start or End fusor's is on the edge. A fusor with no mix point shows the gray marks and no orange one. With no fusor loaded, the strip shows no marks. A Mixed run stops at the orange mark.

On a fusor with an effect tail the player rescales the strip to make room for the tail, so the marks spread over the part before the tail, at 0, 20, 40, 60 and 80% of the strip, the last being End. The End mark is orange, with its triangles widening toward the 0% side and flat on the side facing the tail. Nothing is drawn at the far end of the strip, which is the end of the tail. The part of the strip beyond the End mark, to its right on a left-to-right transition, is the tail. On a tail fusor the countdown counts down to End, so it reads zero when the End mark is reached and stays at zero while the meter runs through the tail.

Settings ▸ General ▸ Mix mark sets when the orange mark shows: Never, Always (the default) or Only in Mixed, which shows it while the Run Mode switch is on Mixed. While the orange mark is hidden, the fusor's mix point shows as an ordinary gray quarter mark. Settings ▸ General ▸ Quarter marks turns the gray marks on (the default) or off. See Settings.

When the countdown warns of a late finish

The = NN.Ns readout has three states beyond counting down normally, each showing whether the run can still finish at its authored end.

• Blink. While the fusor is paused, the countdown blinks starting about three seconds before the point past which the run can no longer finish on time. The blink alternates between white and a dimmed shade. It appears only while the fusor is paused.
• Solid red, during a run. Once the run is going to finish after its authored end no matter what happens next, the countdown turns solid red and stays red for the rest of that run. Red can follow a pause that outlasts the blink, or a setup routine, such as a tempo ramp sync, that takes up enough of the run's time on its own. Either way, red appears for the first time at the moment the run actually becomes late.
• Solid red, before a run. The same red shows from the moment a fusor is loaded, when a run started right now would need more than double the authored pace to make back its setup time. It clears the instant you raise the bar count or load a fusor that fits, and returns if you lower the bar count again. There is no blink in this state, and nothing is shown when Run Mode is set to Manual.

The pre-run red is a warning only: it does not refuse a run or block arming. It does not count everything that consumes setup time: it leaves out a tempo ramp's own sync time, and it counts a pre-run action that waits on the DJ app only if its author entered a fixed duration for it. Where a duration was entered, the entered figure is used exactly, so a duration set too high can show red before a run that would have finished on time. The fix is to correct the entered duration.

Like the picker row, the progress strip is hidden in Pad Mode.

The status line

A single-line strip at the very bottom, with two zones:

• Left side: status messages. Shows the persistent engine state plus capture results and short notifications. The state text updates as you change the Run Mode switch or toggle Start-with-Incoming and Tempo Ramp, which is how those controls confirm.

  The resting states are Unarmed, Armed: move crossfader to start (Manual), Armed: Press Play to start (Auto), Armed: starts with incoming deck and Armed: restart incoming deck to start (Start-with-Incoming), then Playing / Paused in Auto, Manual under a takeover, At mix point: crossfader to the line when a Mixed run has stopped at its mix point, and Completed — stop outgoing deck or press End. at the completion wait. With Tempo Ramp armed, Armed becomes Armed with Tempo Ramp and Unarmed becomes Unarmed with Tempo Ramp.

  Up to one prefix sits in front of the state. In Blind Mode the line reads BLIND – … in gray. Before a successful control state capture it reads UNCAPTURED – … in orange, which is your cue that a transition can't be armed or started until you capture. When Fusor Studio owes a fresh capture but is holding it back because a transition is armed or running, the line reads RECAPTURE PENDING – … in dimmed gray until the deferred capture actually happens. Gray rather than orange or red, because nothing is broken: the control baseline is only stale, and arming and starting work normally while it waits.

  A fourth prefix, NO DJ APP – , appears in gray when no DJ application has been chosen yet. Like UNCAPTURED it means a transition can't be armed or started, and the fix is in Settings → Connection rather than a capture.

  If more than one of these is true at once, only the highest-priority prefix shows, in this order: BLIND, then NO DJ APP, then UNCAPTURED, then RECAPTURE PENDING. A missing baseline is the more serious fact, so it wins over a merely stale one, and having no app at all outranks both.

  Messages and engine states are color-coded by severity so you can read the line at a glance: green for things going right (running transition, fusor loaded, save succeeded), orange for things needing your attention (Armed, Tempo Ramp armed, transition Completed and waiting for you to stop the outgoing deck), red for failures (save failed, action blocked, mode switch rejected), and dimmed gray for idle or informational text (Unarmed, Paused, navigation hints). The status line at the bottom of the Library window uses the same colors.

  Warnings and errors are prefixed with a short code (e.g. CAP5-Uncaptured: run Capture first). Look the code up in Status Messages for what it means and what to do about it.

• Right side: a small telemetry indicator LED.

  Color	Meaning
  Green	Fusor Studio has received MIDI from the DJ app
  Amber	A transition was running and nothing came back from the DJ app
  Gray	Blind Mode

  Amber is the one to watch. It appears when a transition is running and the DJ app goes quiet: during a run the player sends MIDI continuously and the DJ app echoes it, so no MIDI at all usually means the connection is lost.

  Once amber, the light stays amber until Fusor Studio receives MIDI from the DJ app again, including after the transition ends. Only traffic from the DJ app clears it. Touch any control over there, or wait for it to send anything at all, and the light goes green immediately.

  Amber never appears while the Fusor player is idle. A DJ app you aren't touching sends nothing, so silence then is normal and tells you nothing about the connection.

  Amber means the Fusor player was sending MIDI and received none back. It does not stop the transition for you; deciding what to do is your call. See Troubleshooting.

Window behavior

The window has no title bar and no resize handle. The player strip itself is a fixed 384×160 pixels, and Pad Mode preserves that size by reshaping the contents rather than growing the window.

Opening Session View with the expand arrow is the one thing that changes the window's height: the panel opens between the toolbar and the picker row, and the expand arrow closes it again.

Only one copy of Fusor Studio runs. Starting it while a copy is already running does not open a second window: the running window comes to the front, restoring it first if it was minimized. Its status line reads APP1-Launch blocked: already running in orange for about 12 seconds. See Status Messages for the full entry.