Timeline

The Timeline is the primary composition tool. It arranges clips in time across multiple tracks and displays the playhead position.

Anatomy of the Timeline

Tracks

• There is no fixed limit on the number of tracks in a composition — in practice the ceiling is what the machine can decode and draw per frame, not a count.
• Tracks are stacked with Track 1 at the bottom (rendered first, lowest layer).
• Click + Track to add a new track above the current stack.
• Use Insert track above to add a track directly above a specific existing track instead of at the top (new in 3.2).
• Add a Data Track to emit keyframe values over OSC / UDP / TCP / Art-Net / DMX, drive Operator Control readouts, or drive one of Exaplay's own values (a shader parameter, a volume, a clip position) — see Data Tracks (new in 3.2).
• Drag the track header to reorder.

Duplicating a composition copies its full content, including every track (3.2 fixes an earlier case where some tracks were dropped). Right-click a composition tab and choose Duplicate.

Clips

Action	How
Add	Drag from File Browser
Move	Drag the clip body
Trim start (in-point)	Drag the left edge — the clip's In point moves with it and every frame stays where it was in time (new in 3.4)
Extend start	Alt + drag the left edge outwards — the clip starts earlier and repeats to fill (new in 3.4)
Trim / extend end	Drag the right edge
Split	Right-click the clip → Split clip here, or Ctrl + K to split at the playhead (new in 3.4)
Slip (move the media inside the clip)	Alt + drag the clip's picture — the clip keeps its place and length, a different part of the media plays in it (new in 3.4)
Delete	Select + Delete (or Backspace)
Delete and close the gap	Shift + Delete on a single selected clip — its neighbours end up flush against each other (no confirmation)
Close a gap	Click the gap between two clips to select it, then Delete
Copy / paste	Ctrl+C / Ctrl+V
Snap	Hold or toggle with S
Jump to the next / previous snap point	Tab

Select a clip to show its two edge handles. While an edge or a slip is being dragged, a small label next to the pointer shows the In and Out points (or the length) the drag is setting, in media time.

Thumbnail strips

A video clip shows a strip of pictures from its own media: each tile is the frame that plays at that point of the clip, so you can see where you are in a clip and trim or slip to a picture instead of to a guess. The strip follows the clip — trim its start and the pictures slide with it; a clip longer than its media shows the media again where it repeats. Still images show their picture; live inputs, generators and audio clips keep their icon or poster.

The pictures are made by the engine in the background, only for clips a Timeline is showing, and never at the expense of playback: one small frame at a time, at the lowest priority, pausing longer while a show is running. A long clip is covered roughly first and refined afterwards, and until its strip is ready a clip shows its single thumbnail.

While strips are being made, a small Thumbnails label in the Timeline's bottom bar says how far the current one is and how many clips are still waiting — "slowed while the show plays" means it is going slower on purpose. Each such clip shows a thin bar along its bottom edge: filling while its strip is made, striped while it waits its turn. Both disappear when every clip on screen has its strip. Strips are kept next to the media (in its .ep folder) and are made once per file — replacing a file with a new version makes a new strip.

The left edge trims. Dragging it inwards sets a later in-point: the clip's end stays put and the content stays anchored in time — the frame that played at a given second keeps playing at that second — exactly like trimming the head of a clip in an editing program. Dragging it back out restores the earlier frames, down to the start of the media. The same in-point is the In field in the Inspector, next to Out and Duration, so a frame-exact value can be typed instead.

Slipping changes which part of the media a clip plays without moving or resizing it: hold Alt and drag the clip's picture — drag it right to see earlier frames, left for later ones. Only the In point changes (the strip slides under the pointer), and a slip stops where the clip would run past the end of its media, so it never makes a clip repeat. A clip that already plays all of its media has nothing to slip — shorten it first.

Splitting cuts a clip in two at a moment: right-click the clip where it should be cut and choose Split clip here, or put the playhead there and press Ctrl + K. The two parts play exactly what the one clip played — the second starts with the frame that was playing at the cut — and its opacity or volume curve and its keyframes are cut with it, so a fade-out stays at the end where it was. With clips selected, Ctrl + K splits only the selected clips under the playhead; with nothing selected, every clip under the playhead. One Ctrl + Z joins them again. A clip that repeats its media: the second part repeats from where it now starts.

Either edge can extend past the media's length: the clip then repeats to fill its whole duration — so a 10 s loop can cover a 60 s slot. The right edge does that by itself; on the left edge, hold Alt (or keep dragging once the in-point has reached the start of the media) — the clip then starts earlier and repeats, which shifts where each frame falls. When that matters, use the snap: with Alt held, an edge dragged near a whole multiple of the media length settles exactly on it, which keeps the content where it was.

Playhead

• Click anywhere on the ruler to jump to that time.
• Drag the playhead handle to scrub.
• The timecode display in the Transport bar always reflects the playhead position.

Zoom and Scroll

Action	How
Zoom in / out	Ctrl + scroll wheel
Scroll horizontally	Shift + scroll wheel or drag the scrollbar
Zoom in / out	+ / -
Fit all clips	Press F (fit to view)
Go to start	Home key
Go to end	End key
Compact / normal track height	Ctrl + M

Looping

Looping is a property of the clip, not of a region of the timeline: set Loop on the clip in the Inspector. There is no loop-in/loop-out region on the timeline ruler.

Fades

A transition is a fade you set on the clip in Inspector → Fade — Fade to black or Crossfade, with its own length in seconds. Overlapping two clips does not by itself create a transition, and the overlap does not set the fade length. See Fades & Transitions.