The timeline

As many video and audio tracks as you need, frame-accurate trimming, six tools with a letter each, and every edit in an undo history with no floor.

Tracks and clips

Tracks stack, and the stack is the z-order: the track at the top of the timeline is drawn last, over everything below it. Video, audio, text, stills, solids, shape layers and transitions each get their own kind of track, and each kind carries its own colour — matcha for picture, ube for sound, ramune for stills, ichigo for titles, mustard for transitions.

The colour is never the only signal. Every track says what it is in its badge and its name as well, because a channel identity carried by hue alone is one a lot of people cannot read.

A track's header: the grip reorders it, the badge and name say what it is, and the switches at the right silence it, lock it, or turn it into a matte. The twirl opens it into keyframe lanes.

Mute: Audio tracks only. A video track's clips are picture-only — a clip's sound lives on the audio half of its linked pair — so there is nothing on one for a mute to act on.
Lock: The track's clips can't be selected, moved, trimmed, split or deleted, and nothing can be dropped on it. The lane still scrubs, because that reads the timeline rather than editing it.
Matte: The track stops drawing and instead cuts the tracks below it to its own shape. Covered on the effects page.
Reorder: Drag the grip. Reordering changes what is drawn over what.

Linked clips

A video file with sound arrives as two clips on two tracks, linked. Selecting one selects both; moving, trimming, splitting or deleting one does the same to the other. That is what keeps sync a thing you do not have to think about, and it is breakable per pair when you want the sound to run past the picture.

The tools

One mode for the whole editor rather than a toolbox per pane. A tool taken in the timeline is the tool the preview is in as well; a tool with no gesture over the frame simply doesn't appear in the preview's own rack.

The timeline, with the tool rack along the top, the ruler under it, and the playhead reading in the project's own timecode. Run a mouse across this one — it scrubs.

Select V: Move and trim clips · click the frame to pick the layer under the cursor
Scrub S: Drag anywhere to move the playhead
Cut C: Click a clip to split it there
Splice X: Click a clip to remove it and close the gap
Trim Y: Drag an edge to roll the cut · drag the middle to slip the shot · ⌥ to slide it between its neighbours
Hand H: Drag to pan — the timeline, or the frame in the preview

The rest act on the frame rather than on the strip, and are covered on The canvas: Pen, Shape, Crop.

Trimming

Dragging a clip's edge with the Select tool is an ordinary trim: the edge moves and leaves a hole, or stops against its neighbour. That is the right edit while you are still deciding how long a shot is.

Once the sequence is assembled the question changes from "how long is this shot" to "which part of it, and where does it hand over", and the three edits that answer it all keep the cut tight. All three live under the Trim tool (Y), told apart by where you take hold rather than by arming a mode: the edges roll, the middle slips, and ⌥ turns the middle into a slide. The cursor says which one is under the pointer before the drag starts.

The same two shots, three ways. Roll moves the cut between them and the sequence keeps its length. Slip changes which frames of the file a shot shows without moving anything. Slide moves a shot and its neighbours give up and take back the frames it passes over.

Deleting

Delete: Remove the clip and leave the hole
Shift + Delete: Remove it and close the gap — a ripple delete
⌘/Ctrl + X: Cut to the clipboard, rippling
X: The Splice tool: click a clip to remove it and close the gap

Snapping, marks and the loop

Clips latch onto the things worth landing on — the playhead, a clip's edges, the in and out marks, the start of the timeline — with a mark drawn where the catch happened. Nturns it off when you want a frame that isn't any of those, and K toggles the same magnetism for keyframes.

I: Mark in at the playhead
O: Mark out at the playhead
⌥ + X: Clear both marks
L: Loop the marked region while it plays
F: Follow the playhead — the view scrolls to keep it in frame

The marks are not only a loop. The export dialog will render just the stretch between them, which is the fastest way to check a section without waiting for the whole piece.

Speed, ramps and freezes

A clip has one rate, and it keyframes like any other control. A constant rate is the ordinary case — half speed, double speed — and an animated one is a ramp: the shot accelerates, or slows into a beat, or stops and comes back.

It lives in the effect palette as Retime, which is also what it answers to if you search "speed", "slow motion" or "reverse". Adding it changes nothing on its own — it opens at real time — and it sits above the effects on the clip rather than among them, because a retime decides which frames the rest of them have to work on.

The rate on top, the source frames underneath. Where the curve is high the clip eats through its file quickly and the frames crowd; where it dips they open out. A ramp through zero runs the shot backwards.

A negative rate is reverse. It is not a separate mode — reverse is simply a rate below zero, and a ramp that passes through zero is a shot that stops and comes back.
A freeze frame holds one instant of the source for the whole clip. It survives moving, trimming and splitting, because a hold is a place in the file rather than a speed.
Retimed clips still trim, split and snap normally. The arithmetic is done once, in one place, so the picture, the sound, the filmstrip and the render never disagree about which frame is up.

Keyframes on the track

A clip carries a strip of diamonds showing where it animates — one mark per moment, whatever was keyed there. That is the right summary for a 46-pixel lane and the wrong handle the moment two properties are keyed at the same instant, because they are one diamond and neither can be dragged without the other.

Twirling a track open splits that strip into one row per animated property, laid out on the timeline's own ruler. Two clips animating opacity share one Opacity row.

Drag a key in a lane to move it in time — only in time, because the question a timeline answers is when. The value belongs to the curve editor, which has an axis for it.

Double-click a lane to add a key at that moment, or a key to take it away. The full picture is on Keyframes.

Transport and view

Space: Play / pause
← / →: Nudge the playhead one frame
Shift + ← / →: Nudge one second
Home / End: Go to the start / the end
+ / −: Zoom the timeline in / out
⌘/Ctrl + wheel: Zoom at the cursor
Drag empty track: Box-select clips — ⇧ or ⌘/Ctrl to add