Features

Everything the app does today, with the intent behind each. Kept mechanically true to the code; "planned" items live in [[Roadmap]].

Projects

Home screen with a Create project card and canvas presets named for where the video goes (16:9 YouTube, 9:16 TikTok/Reels/Shorts, 1:1, 4:5, 21:9), and searchable project cards with thumbnails. Delete moves a project to Recently deleted at once, with Undo on the toast; there it waits 30 days (Restore, or Delete forever, which asks twice) and is then deleted for good. Agents never see it there ([[ADR-078 Deleted projects wait in Recently deleted, marked in their summary]]). Rename (in place, without opening) and Duplicate ("Name copy", sharing the same media files) sit on each card, as in CapCut, and in its right-click menu (Open, Rename…, Duplicate, Delete). A list view beside the search (CapCut's toggle) shows a row per project with its canvas, length and last edit; the choice is remembered per viewer.
Canvas size in pixels (project Details > Size, CapCut's custom ratio): any width and height from 16 to 8192, rounded to even numbers as encoders need; set_project also takes the frame rate.
Autosave 800 ms after every change, never overlapping; "Saved 10:42" in the title bar; Ctrl+S saves now. No save dialog, as in CapCut.
Safe project switching: edits made during a slow save are persisted before leaving; overlapping navigation requests are ignored. Save errors keep the project open. Home shows a loading status and supports keyboard opening/deletion without triggering both actions.
The first clip sets the canvas size and frame rate on an empty timeline, so phone footage makes a vertical project — unless a canvas was chosen (a Home preset or the Details ratio), which it then keeps.
No empty drafts: a new project is saved once something is done in it; pressing Create and leaving at once keeps nothing on Home (undoing every edit counts as nothing done) ([[ADR-073 Templates land as a block and the web keeps what it imports]]).
Open JSON format ([[Project format]]).
Save a copy: named independent edit versions, optionally opened after saving; source media stays shared. Failed writes keep the original open.

Media

Import from the picker, by dropping files anywhere in the window, or on the timeline (which also places them).
Web build: imports by address are kept in the browser's storage, as picked files are, so a project keeps playing when the address goes away; a toast shows the copy. Over 1 GB a file stays linked to its address, and a toast says so.
Formats the platform decodes: MP4/MOV/MKV/WebM with H.264, HEVC (where the OS has it), VP8/9, AV1; MP3, WAV, AAC/M4A, FLAC, Ogg/Opus; PNG, JPEG, WebP, GIF, AVIF. On desktop, what the webview cannot decode (ProRes, DNxHR, MPEG-2...) gets an FFmpeg proxy when FFmpeg is installed; the web build refuses it with the codec named.
Gapless MP3: an MP3's encoder delay and padding (its LAME tag) are left out of its playback, export, waveform, analysis and length, so it lines up with other material sample for sample, as ffmpeg plays it; an AAC file's priming was already left out by its edit list ([[ADR-112 An MP3 plays without its encoder delay, as ffmpeg plays it]]).
Background filmstrips and waveforms, two files at a time.
Hover scrub on video cards, as in CapCut: moving across a card shows the frame under the pointer, with a line, from the timeline's thumbnails (nothing extra decodes).
Phone footage rotation honored.
Media organization: combined name/type/used/unused filtering; import order, natural name and source-duration sorts; grid or compact metadata list. Usage counts select all referencing clips and seek the earliest. Counts follow edits/Undo, including references on inactive tracks.
Record from the camera or the screen (CapCut's Record; Media > Record, beside Import): a live pill with the elapsed time, Stop or Discard; the take (MP4 where the webview can record it, else WebM) is imported and placed at the playhead it started from. Checked in the web build with the browser's fake camera; the desktop app's camera and screen permissions are not checked yet.
Remove media (Premiere's Clear and Remove Unused): right-click a media card for Add to timeline, Preview, Favorite and Remove from project; a file the timeline uses offers to take its clips with it. Manage media removes every unused file at once (remove_media). The files on disk are never touched; one undo step each.
Media recovery: Manage media checks editing-source availability; Locate and Relink repair every clip reference while preserving edits, with Undo. Replacements require compatible streams and full source duration; a clip of a whole file relinks to that file (ADR-117).
Rename media (right-click a media card > Rename, or in the grid view double-click its name; rename_media): the project's name for the file, which stays as it is on disk; clips without a name of their own follow it. In the grid a double-click on the name renames and the rest of the card adds the file to the timeline; in the list view, a row's double-click always adds.
Folders and favorites: saved virtual folders, undoable folder rename/delete and assignment, plus intersecting folder/favorite filters.
Source preview: independent video/audio transport, scrubbing and frame stepping, In/Out range insertion, and still image preview. Add range places the range as the timeline would (CapCut); Insert (,) splits at the playhead and pushes what follows, Overwrite (.) covers what is there (Premiere's), on the main track or the first audio track.

Timeline

CapCut's toggles: main track magnet (gapless, reorders on drag, including a drop at the very front), snapping with a cyan guide, linkage (titles, overlays and sound effects follow the shot under most of them through ripples and reorders; music beds covering two or more complete shots stay put, even when one shot is longer), preview axis (hover to preview).
Undo history: right-click the toolbar's Undo or Redo for the last 20 steps by name, nearest first; choosing one goes back (or forward) to it (VEGAS's undo list, Premiere's History panel). Agent edits use readable labels too, such as "Add clip", "Change opacity", "Change border width" and "Deactivate clip" ([[ADR-109 What an agent can set, a person can see and change]]).
Select and blade tools; split, split all, delete left/right (Q/W), delete, ripple delete; freeze frame; mirror; rotate 90°; extract audio; deactivate clip (one switch for the whole selection: a mixed one goes off, an all-off one comes back on); markers; in/out range (a cyan band on the ruler, which stays in view as the tracks scroll).
Linked picture and sound (Premiere's linked clips, for J and L cuts): Extract audio keeps the video and its sound linked as a group, so they select, move and delete together; Alt-click takes one side alone, each edge trims on its own, and red frame counts (+15 / −15) show on both when one is moved out of sync. Ungroup unlinks them.
Marker management in the library and View menu: search notes or timecodes, filter by color, jump between notes, edit exact positions and labels, and undo deletion. Delete shown removes what the search and color filter show (a run of beat markers, say) in one undo step. A marker that follows a clip (a song's beats) names its clip and can be detached; search finds it by the clip's name ([[ADR-119 A person corrects a song's grid and cuts its bars, markers say what they follow, and the check hears its joins]]). Double-click a ruler flag to edit it. Markers beyond the last clip remain reachable without extending export duration.
Export marker text: preview and save the displayed notes as exact timecodes or YouTube-style chapter timestamps. Search/color filters choose the exported set; chapter timing checks surface issues before saving.
Drag to move (across tracks, above the top track for a new one), Alt-drag to duplicate, edge drags to trim (ripple on the magnetic main track), marquee select, Ctrl+wheel zoom at the cursor, ruler scrub, page-flip follow during playback, right-click menu.
The clip menu (right-click a clip; CapCut's and Premiere's): Cut, Copy, Paste, Duplicate, Delete, Ripple delete; Split, Speed… (opens the inspector's Speed tab), Reverse (a check: every selected clip that can play backward turns, by set_reverse's own rule), Freeze frame, Extract audio, Replace clip; Copy effects and Paste effects (the inspector's effect clipboard, onto every selected clip that takes effects); Rename, Group, Ungroup (always listed, off unless a selected clip is grouped), Activate, compound clips; keyframes, range and Label. Every row runs the action or command the rest of the app uses. A menu taller than the window scrolls inside it.
Library drags land where the preview shows, by CapCut's rules: video and images dropped above the tracks become a picture-in-picture overlay on a new track at the drop time; on the magnetic main track they insert at the nearest cut, never splitting a shot, and the later shots (with what linkage carries) slide aside to open the gap, with a bar at the cut. A busy row opens a new track, shown where it goes in; effects and filters outline the clip they attach to (on empty timeline, a layer there, whatever is selected); a transition marks its cut. The preview is a dry run of the drop itself ([[ADR-046 A drop preview is a dry run of the drop]]).
Group clips (Ctrl+G; Ctrl+Shift+G ungroups; Edit menu and right-click; group_clips, ungroup_clips): grouped clips select, move, copy and delete together across tracks, each keeping its own settings; Alt+click picks one alone, as in Premiere. Pasted copies form their own group.
Rename clips (right-click > Rename, or double-click the name on a clip's strip; rename_clip; Premiere's Rename): the name shows on the timeline instead of the file's name, a title's words or an effect layer's effects; an empty name gives the default back. Titles keep CapCut's double-click for their words, so they rename from the menu. One undo step each.
Clip labels (right-click > Label; set_clip_label; Premiere's Label, Resolve's Clip Color): eight muted colors paint the selected clips' body and name strip, so an edit can be sorted by eye. Splits and copies keep the label.
Compound clips (Alt+G, as in CapCut; Alt+Shift+G breaks one apart; Timeline menu and right-click; create_compound_clip, break_compound_clip, edit_compound): the selected clips, on any tracks, become one green clip that plays them as a nested timeline. Its own speed, transform, opacity, blend, color, effects, mask, animations, transitions and volume act on the whole, the way Premiere's nests do; its filmstrip and waveform show what is inside. Double-click it to edit inside, with a breadcrumb above the timeline to go back out; every compound clip that plays it changes. Break apart puts the clips back where they were. One undo history covers every level, saving and export take the whole project wherever you are, and OTIO carries it as a nested stack ([[ADR-037 Compound clips are nested timelines composited to a texture]]). duplicate_clips with unique: true copies a compound clip with a timeline of its own, so a styled precomp (a floating window) is a template whose copies take other footage (edit_compound replace_clip).
Replace clip (right-click, as in CapCut; replace_clip): pick a file and it takes the clip's place, keeping its start, length (shorter only if the new source runs out), transform, effects, animations and sound settings; video and pictures swap freely, sound for sound.
Keyboard reach on the timeline: Tab lands on the selected clip (or the first), arrows move between clips and tracks with a focus ring, and every edit key acts on it; screen readers hear its name and span.
Lift and Extract (Premiere's ; and ', Timeline menu; lift_range): take the in/out range out of every unlocked track, cutting clips at its edges; Lift leaves the gap (the magnetic main track closes its own), Extract closes it. The marks clear after.
Close gap: right-click an empty stretch of a track for Close gap (ripple the clips after it left) or Close all gaps on this track (Premiere's ripple delete of a gap, Resolve's Delete gaps; close_gaps).
Nudge clips by a frame with Alt+Left/Right, five with Shift (Premiere's keys; nudge_clips), all or nothing: never past the start or over another clip.
Keyframed pan: the Audio tab's Pan row (and the keyframe panel) animates pan like volume; a track's pan and a compound clip's add to it.
Channels (Audio tab; set_channel_fill; Premiere's Fill Left and Fill Right): play one channel on both sides, for a lav recorded on one side; a mono file is upmixed first, so either choice keeps it whole. Paste Attributes copies it with the sound.
Equalizer (Audio tab): low shelf (120 Hz), mid bell (1 kHz) and high shelf (8 kHz), -12 to +12 dB, on audio clips, a video's own sound and a compound clip (over the mix of everything in it); the same biquads in preview and export; copied by Paste Attributes with the rest of the sound.
Compressor (Audio tab; CapCut's Enhance voice, Premiere's Dynamics): Off, Enhance voice, Gentle or Strong, then threshold, ratio and makeup; after the EQ, before volume, the same node in preview and export, and Normalize loudness measures through it. Evens out speech so export loudness reaches its target without heavy limiting ([[ADR-053 One compressor everywhere, measured as it plays]]). On a compound clip it compresses the mix of everything inside as one bus, after its EQ and before its volume and fades; export's windows start a second early so a compressor never starts cold ([[ADR-100 A compound clip's sound is a bus, and a bed keeps its balance in every take]]).
Sound crossfades under transitions: a video transition between two clips with sound overlaps their audio across the cut by half the transition each way (as far as both have handles) at constant power, Premiere's default audio transition, in preview and export alike.
Audio crossfades and music cuts (agents: set_crossfade, cut_music): an audio clip crossfades into the next on its track at equal power over the seconds before the cut; cut_music takes bars out of a song on its grid and joins the pieces so the beat runs on. A split of one sound plays on with no click guard at the cut, its halves through one EQ and compressor (ADR-117). preview_audio measures every join, click and dropout ([[ADR-104 Voice and sound an agent can trust without ears]], [[ADR-107 A split plays on, a cut keeps its downbeat, and a duck follows its music]]). A person makes a crossfade with the audio clip menu's Crossfade into next clip (the transitions' default length, as far as the join allows, or why none fits), sees it drawn at the cut like a transition, and sets its length in the Audio tab's Crossfade row ([[ADR-109 What an agent can set, a person can see and change]]); a transition dropped on the join of two audio clips makes the same crossfade ([[ADR-111 A person checks the project, Space presses what the keyboard reached, and a transition on sound crossfades]]). A song's clip menu has Cut bars: the In to Out range on the song's nearest bar lines, through cut_music, named with its count ([[ADR-119 A person corrects a song's grid and cuts its bars, markers say what they follow, and the check hears its joins]]).
Track header: Solo on audio tracks (while any track is soloed, only soloed tracks sound); right-click for Rename (or double-click), Solo, Track volume and pan (a dB fader and a pan slider added to each clip's pan, one undo step per drag), Small/Normal/Large height and Delete track. Agents: update_track (solo, height, pan) and delete_track.
Audio clips: draggable volume line (Shift for fine) and fade knobs; a selected video's own sound has them too, on its waveform strip (the whole range there takes 60 px of travel, the strip being 14 px tall).
Record voiceover (the microphone in the timeline toolbar, as in CapCut): pick the input, optionally mute the project, then a 3-second countdown and the timeline plays from the playhead while recording. Stop keeps the take as Voiceover N.wav on an audio track, starting on the playhead's frame; Discard or Escape keeps nothing. The samples run on the playback clock, so the voice lands where it was heard, corrected for output latency, with the pre-roll dropped.
Pro trim tools: ripple (T), roll (R), slip (Y) and slide (U), with readouts of what moves while dragging.
Rate stretch tool (Shift+R, Premiere's Rate Stretch): drag a clip's edge and its speed changes so the same source fills the new length (0.1x to 100x); the end ripples later clips, the start stops at the clip before. Clips with a speed curve or a freeze keep their length.
Two-up trim preview: actual clip-edge frames for trim/ripple/roll/slip/slide, clamped source times, one-step Undo and gesture cancellation. In a short player the frames shrink so its header and footnote always show.

Workspace

Proportional panels: library, player, inspector and timeline sizes are kept as shares of the window, so a bigger screen grows them all (CapCut's behavior). Drag the splitters (double-click resets one); View has Default, Large preview and Large timeline layouts and Reset layout.
About (Help > About, on Home and in the editor): name, version and platform; the GPL-3.0-only license with a link to its text; links to the source code, the user guide and [[Third-party licenses]]; and the open-source packages the app uses directly, with versions and licenses, read from package.json, the installed packages, Cargo.toml and Cargo.lock when the app is built (src/lib/about.ts), so the list cannot drift. The desktop app opens these pages by name through Rust (about_open), never a URL from the webview; the web build opens a tab.
Preferences (the gear in the title bar, Edit > Preferences, Ctrl+,; Home too; Premiere's Timeline preferences): the lengths new pictures (5 s), titles and effect layers (3 s) and transitions (0.5 s) start at, and audio scrubbing. Per viewer, kept with the keymap and layout, never in a project.

Viewer

WebGL2 compositor: transforms, crop, 13 blend modes (CapCut's 11 plus Add, Difference, Exclusion), chroma key, masks, color adjustments, 26 effects (Blur up to a 300-pixel radius at 1080p, amount 500, for big soft glows: past the old maximum of 100 it runs on a downsampled pyramid, and up to 100 it draws exactly as before, [[ADR-069 Large blurs run on a downsampled pyramid]]; CapCut's Reduce image noise, Motion blur, Sketch and Halftone, Premiere 26.3's Magnify: a round lens with its center, size, zoom and feather, keyframable to follow a pointer in a screen recording, and Zoom and Letterbox for epic edits; every pixel size is pixels at 1080p, so the viewer and the export draw an effect alike, and Glow, Reduce image noise and Sketch take a radius or line width, [[ADR-117 A whole file relinks to itself, effects keep their size at every render size, and a split's halves share one compressor]]), 24 transitions, 17 looks, adjustment layers. The Strobe flash starts at 2 flashes a second: more than 3 can trigger seizures (WCAG 2.3.1), so keep it there.
Masks (Video > Mask, CapCut's shapes): linear, mirror, circle, rectangle with round corners, heart and star, with feather and invert; every number takes keyframes, and a rotated mask turns rigidly on any picture shape ([[ADR-049 Masks turn rigidly and grow shapes without new fields]]). While the Mask tab is open the viewer draws the mask's outline on the picture, rotated and mirrored with it: drag inside to move it, the edge handles to size it, the knob to turn it (45° catches; Ctrl turns freely), the arrow to feather it and a rectangle's corner dot to round it. Each drag is one undo step and keys animated numbers. set_mask with at keys the values it is given there, from what the mask held at the clip's start ([[ADR-120 Callouts and overlays pinned to footage, and frame_region moves]]).
On-canvas handles: move, scale, rotate. A moved picture snaps its edges and center to the canvas's and to other visible pictures', and to the safe margins and thirds while those viewer guides show, with a guide at the line; Ctrl moves freely, Shift keeps one axis.
Viewer selection uses the picture's on-canvas box, top track first, skipping hidden and locked tracks. Empty canvas or stage space deselects; rotation and crop use the same geometry as the transform handles.
Several pictures at once (a multi-selection or a group): the viewer draws one box around the selected pictures showing under the playhead, each outlined inside it. Drag inside to move them all, with the same edge and center snapping; drag a corner to scale them together about the box's center, positions and sizes alike. Each drag is one undo step. Clicking a grouped picture on the viewer selects its group, as on the timeline (Alt picks it alone).
Crop on the canvas (CapCut's Crop): the crop button in the timeline toolbar or the Crop section of the inspector shows the whole picture with the crop drawn over it, dimmed outside. Drag the eight handles, or the crop itself; ratios under the viewer (Free, Original, 16:9, 9:16, 1:1, 4:3, 3:4, 4:5, 21:9) crop the largest centered area of that shape and keep it while dragging. Reset, Cancel (or Escape) and Done (or Enter); Done is one undo step. Works on rotated and mirrored pictures ([[ADR-048 Crop is cut from the source and edited on a copy]]).
Fit / Fill / Stretch under Transform (Resolve's and Premiere's framing; frame_clips): fit shows the whole picture, fill covers the canvas and crops the overflow, stretch covers it exactly; each centers.
Motion path (Premiere's): a selected picture whose position is keyframed shows the dashed line its center travels, with a dot at each position key, so a tracked or reframed path reads at a glance.
Flip buttons under Transform (horizontal and vertical; set_flip), and arrow keys on the viewer after clicking it nudge the selected pictures 1 px (Shift: 10 px); a held key is one undo step, and the arrows step frames everywhere else.
Align (CapCut's Transform row): left, center, right, top, middle, bottom against the canvas; with several clips selected, against their combined bounds, plus distribute for three or more ([[ADR-045 Align measures the resting box, one clip to the canvas]]). Inside title safe makes one clip stop at the title-safe line (the viewer's Title 90% guide) instead of the canvas edge.
Frame-exact: the framecode drive proves the right source frame at 1x, 2x and 0.5x across GOPs and backward seeks; the speed drive proves it for every frame of a ramp, a reversed ramp and a reversed clip.
Playback on the audio clock with output-latency compensation; J/K/L shuttle; Go to start and Go to end buttons around the frame steps in the transport (CapCut's and Premiere's, the keymap's Home and End actions, so their tooltips name the keys as rebound); Loop (the transport's repeat button, Mod+L) goes round the in/out range when it holds the playhead, else the whole timeline; Play in to out (Mod+Shift+Space, Premiere's key) plays the range once; click the current timecode to type where to go (Premiere's Playhead Position): a timecode, digits read right to left (1000 is ten seconds), or +/- an offset (+15 is fifteen frames on); preview resolution Full/½/¼ (auto ½ above 1080p while playing).
Audio scrubbing (CapCut's, Premiere's "Play audio while scrubbing"): dragging the playhead on the ruler while paused plays 90 ms snippets of the mix where it lands, one after another, through playback's own scheduler, so every effect and fade is heard; never while playing. Preferences > Playback turns it off ([[ADR-079 Audio scrubbing plays snippets through the playback scheduler]]).
Stereo peak meter, and a loudness line under it (Premiere's Loudness Meter in one row): momentary, short-term and integrated LUFS of what plays (EBU R128, an AudioWorklet K-weighting the master bus), integrated since play started; it stays after a stop. On the drive it agrees with an offline BS.1770 measurement within 0.3 LU.
Viewer zoom (Premiere's Program monitor zoom): Fit or 25 to 400 % of the project's own pixels from the transport, Ctrl+wheel to zoom at the pointer, the wheel (Shift: sideways) or a middle-button drag to pan; the handles, guides and crop and mask tools follow.
Ratio menu in the transport bar, as in CapCut: change the canvas shape (16:9, 9:16, 1:1, 4:5, 4:3, 3:4, 21:9) without leaving the clip being edited; the short side is kept, and Undo restores the size.
Composition guides in the Player header and View menu: safe margins (93% action / 90% title, SMPTE ST 2046-1), rule of thirds, or both, and TikTok, Reels, Shorts: the parts of a 9:16 frame the apps' buttons, captions and header cover are shaded (the largest of each side in their ad specs: 14% top, 35% bottom, 11% left, 19% right), and dragged pictures snap to the clear area's edges. Follow the canvas in portrait and full screen; preview only, excluded from exported pictures. The action box is labeled at its top and the title box at its bottom, so the labels never meet on a small picture.
Canvas fill behind letterboxed clips: blur or color (CapCut's Canvas).
Scopes (Player header or View menu): luma waveform, RGB parade, vectorscope with 75% targets and the skin-tone line, and histogram, of the graded output; live while paused, 8 updates a second while playing ([[ADR-022 Scopes bin a GPU-downscaled readback on the CPU]]).

Graphics and compositing

Shape layers (After Effects' shape layers, ADR-057): rectangle, rounded rectangle (1 is a pill), ellipse and line, with a solid or two-color gradient fill, an outline, and a draw-on amount (Trim Paths) that runs round the outline from its top center or along a line from its left end. Width, height, corners, outline thickness, draw and gradient angle all keyframe; drawn by the GPU at any size, so edges stay crisp at 4K and under any scale or rotation. The Shape section of the Video tab edits them; the timeline names the clip after its shape. The pieces of lower thirds, callouts, CTA buttons and end cards (add_shape, set_shape).
Callouts (ADR-120): a ring, box or rounded box that draws on around a part of a screen recording or shot, the rest of the frame dimmed through a hole the same shape, both pinned to that clip's picture, so they stay on the part through its zooms and pans and glide on to other parts; an optional click as the ring draws on. Two grouped shape layers (the dim under the ring) that edit like any shape. Library > Adjustment > Callout adds one on the video under the playhead; drag the ring onto its part and the hole goes with it (add_callout).
Pinned to footage (ADR-120): a title, shape or sticker pinned to a point of a clip's picture follows that clip's position, scale and keys, frame_region's zooms included, through every later edit; moved by hand it is pinned where it lands. Animation > Tracking shows what a layer is pinned to, with Pin to footage and Unpin (anchor on add_text and add_shape, set_anchor).
Soft light (ADR-069): a shape's radial gradient (from the center to its rim, an ellipse fitting the box, with a center and radius that keyframe) and feather (the shape blurred: the edge fades over that many pixels with a Gaussian's falloff, and a long ellipse feathered wider than it is tall stays one smooth glow, ADR-099) make soft background glows without image files; with the Blur effect at 300 to 500 they are as soft as any launch film's. Kind (Linear, Radial), Fade out, Radius, Center and Feather in the Shape section.
Drop shadow on pictures (After Effects' Drop Shadow, ADR-070): any video, image, title, shape or compound clip casts a soft shadow (color, blur up to 600 px, offset, opacity, all but the color keyframable). It is cast by the finished picture, after its mask, crop, effects and track matte, so a rounded window casts a rounded shadow and a compound clip (footage, a border and a bar) casts one shadow for the whole floating window. Shadow section of the Video tab (set_shadow).
Border on pictures (After Effects' Stroke layer style, outside, ADR-099): any video, image, title, shape or compound clip gets a border around its finished picture (color, width up to 200 px at 1080p, opacity; width and opacity keyframe). It follows the picture's edge after its mask, so a rounded picture-in-picture gets a rounded frame and a circle mask a ring; it keeps its width however the clip is scaled, fades with the clip, and the drop shadow is cast by the picture and its border together. Border section of the Video tab (set_border); a title shows its drop shadow, border and colorize in its Text tab while it has them.
Perspective tilt (CSS rotateX and rotateY, ADR-070): Tilt X and Tilt Y in the Transform section turn a picture in depth, seen from a camera 2000 pixels (at 1080p) in front of the canvas center, the picture drawn perspective-correct; both keyframe, so a window swings into place, and its shadow follows it (set_tilt).
Track mattes (After Effects', ADR-056): a clip shows only where another clip's picture is opaque (Alpha) or bright (Luma), or the reverse: video inside text, logo and wipe reveals. The matte is the clip on the track directly above (keeps working after cuts) or a named clip; it is not drawn itself, and its own animation animates the reveal. Preview and export match to the level (set_track_matte; Compositing section of the Video tab).
Motion blur from movement (ADR-058): a clip that moves (keyframes, in/out animations, wiggle) is averaged over a 180-degree shutter (or any angle to 720), with more samples the faster it travels; slides, pushes, zooms and spins between clips blur too. Full quality paused and in export, lighter while playing; still frames cost nothing (set_motion_blur).
Mirror edges (Motion Tile's, ADR-059): a picture moved, shrunk, spun or shaken off the canvas fills it with mirrored (seamless) or repeated copies instead of black (set_edge_mode).
Wiggle (After Effects' wiggle(), ADR-062): seeded smooth noise on position, rotation or scale for camera shake, nervous titles and floating logos, in pixels, degrees and percent; its strength keyframes to ramp a shake in or out, and the same seed repeats the same path (set_wiggle).
Spring, Elastic and Bounce eases for keyframes, overshooting and settling exactly on the next value (ADR-062).

Inspector

Adding a transition or clicking its timeline marker opens its Transition settings immediately. Choosing another tab returns to that clip's controls.
CapCut's tab matrix per clip type: Video (Basic, Remove BG, Mask), Audio, Speed, Animation (In/Out/Combo or Loop), Adjust (filter and color), Effects (applied stack with its count), Text, Captions, Transition; project Details when nothing is selected.
Applied effects have their own inspector tab, with enable/disable and removal controls, top-to-bottom reordering, reset including effect keys, Enable/Disable all, and undoable Remove all. Text/captions are supported. Tabs wrap at narrow widths so none are hidden offscreen.
Copy/Paste effects between visual clips (including text/captions and adjustment layers), or onto a multi-selection in one undo step. Appends independent effect instances and animation; preserves existing effects and other clip settings. A session clipboard keeps normal clip/keyframe copying separate ([[ADR-038 Copied effects preserve animation and get new identities]]).
Anchor point (Premiere's): Anchor X/Y under Transform, as shares of the picture's size from its center. The anchor sits at the position, and scale and rotation (inspector, handles, keyframes) turn about it; the viewer marks it with a crosshair. Align still lines up the picture.
Uniform scale switch under Transform, as in CapCut: off splits Scale into Scale X and Scale Y (keys copied, so nothing jumps); on joins them. Corner handles keep a stretched picture's proportions.
Every color field has a pipette where the platform has the EyeDropper API (WebView2, Chromium): pick a color from anywhere on the screen, the viewer included (a text color from the footage, a chroma key's green before keying).
Every numeric row: slider, typed value with units, reset, keyframe cluster (‹ ◇ ›); keyframed properties auto-key at the playhead.
One drag, one undo step, on every slider (held arrow keys too) and on the color picker's square ([[ADR-072 One drag is one undo step and a typed value is kept]]).
Typed values are kept however focus leaves the field (Enter, Tab, clicking another clip); Escape reverts. An empty or non-numeric entry changes nothing, a decimal comma reads as a point ("1,5" is 1.5), and a unit after the number is ignored.
Sections remember being open or closed, per section, across clips and reloads (in this browser, like the layout). A switch that opens rows (Low-pass, Reverb, Echo) scrolls them into view.
Several clips at once (Premiere 25's Properties panel): with more than one clip selected, Scale, Rotate and Opacity for the pictures and Volume for the clips with sound set all of them, one undo step; a value they disagree on shows "Mixed" until it is set.
On a keyframe, an easing button beside the cluster opens the presets; the Transform header's ◇ keys (or unkeys) all four of its properties at once, as CapCut's section diamonds do.
Reusable effect presets: local named stacks with animation, rename/delete, cross-project reuse and undoable application to unlocked visual clips.
Paste Attributes: choose transform (with crop, opacity, drop shadow and border), color, audio (with EQ and compressor) and/or effects, with animation retiming and optional effect replacement. Clip timing stays intact.

Keyframes

Keyframe animation panel (CapCut's Show keyframe animation: toolbar, clip right-click menu, or its shortcut), docked under the tracks on the same time axis ([[ADR-023 The keyframe panel docks under the timeline tracks]]): one lane per animated parameter, and a value graph of the focused one in inspector units. Drag keys in time and value (Shift locks an axis, the axis holds still mid-drag), drag bezier handles on a selected key's segments, Shift+click to add, box-select, click to seek; one-click keys for a clip with none.
Easing presets wherever keys are selected, with curve previews: Linear, Hold, Ease in, Ease out, Ease in-out, Smooth, Fast in, Overshoot (passes once, no bounce), Anticipate, Spring, Elastic, Bounce. Smooth to Anticipate and hand-drawn curves are stored as CSS beziers; Spring, Elastic and Bounce are named curves no bezier can draw (ADR-062).
Diamonds on the selected clip: click to select (Shift/Ctrl adds), drag to retime with snapping to the playhead and the other keys, right-click for easing, double-click to seek; the tooltip names what is keyed at that frame.
Delete, Copy, Paste and Escape act on selected keyframes before clips ([[ADR-024 Keyframes are selected by path and frame, and keys come first]]); paste lands at the playhead with spacing kept. A moved key replaces one it lands on, and keys stay inside their clip.

Color

CapCut's Adjust sub-tabs with Resolve and Lumetri math underneath ([[ADR-020 The grade lives in adjust, in Lumetri's order]]):
- Basic: filter looks and the temperature, tint, saturation, vibrance, hue, exposure, contrast, highlights, shadows, whites, blacks, sharpen, grain, fade and vignette sliders, and Colorize: the picture's brightness in one color (white becomes it, black stays), with a keyframable amount, so a white glow or logo can be made amber, which warming cannot do (set_colorize, [[ADR-105 Answers hold what was asked, tracked titles center on their letters, pictures take a color]]).
- HSL: eight color ranges, hue, saturation and lightness each; only that color changes, grays never.
- Curves: luma, red, green and blue; click to add a point, drag to shape, drag off the graph to remove; arrow keys nudge. Monotone cubic, so a curve never overshoots its points.
- Color wheel: lift, gamma, gain and offset pucks (a vectorscope's geometry, so the wheel and the scope agree) with luminance rings.
- LUT: import a 1D or 3D .cube (or drop one on the window), pick it, set its intensity ([[ADR-021 LUTs are files by reference, sampled as 3D textures]]).
Auto adjust (Adjust > Basic, CapCut's): corrects exposure, levels and white balance from the clip's own frame at the playhead, measured with its adjustments off. Exposure only moves a median outside 0.35-0.65 and never brightens the brightest 0.2% past white, so a frame dark by design (a dark-theme app, a night scene) is left as shot; white balance reads the midtone neutral pixels and leaves a frame of saturated color alone; every value stays within moderate limits. One undo step; auto_adjust for agents.
The grade runs on clips and adjustment layers alike, every number is keyframeable, and preview and export render it with the same shader.
Agents: set_hsl, set_curve, set_color_wheel, apply_lut, and window.videoEditor.importLuts.

Speed

Standard: one rate, 0.1x to 100x, with quick picks; the clip keeps its source and later clips move with the new length. Or type the Duration (CapCut's) and the speed follows, the same source filling it.
Frame blending (Speed > Playback; set_frame_blending; Premiere's Time Interpolation): slow motion, or a source rate unlike the project's, mixes neighboring source frames instead of repeating them, in preview and export ([[ADR-051 Frame blending draws the layer twice from two cursors]]).
Curve (CapCut's curve speed): None, Custom, Montage, Hero time, Bullet time, Jump cut, Flash in, Flash out, and a graph editor. The graph has a log speed axis from 0.1x to 10x, draggable points, add at the playhead, delete, reset, a playhead line and the live duration. The line drawn is exactly what plays, and trims and splits keep the ramp ([[ADR-027 Speed curves are exponential and anchored to clip frames]]).
Reverse: frame-exact, on any GOP length, with sound reversed too. Reversed 1080p plays without dropped frames ([[ADR-028 Reverse and retimed sound are made in the engine]]).
Change pitch: off by default, as in CapCut. Voices keep their pitch at any speed and through ramps; on, pitch follows the speed like tape. Sound stays within a frame of the picture in preview and export.

Text and captions

Text presets (title, lower third, outline, neon, caption, quote, label) with font, size, color, bold/italic/underline, alignment, spacing, stroke, shadow, background box, in/out/loop animations. A new title wraps inside the safe area where it stands (titleWrap): a centered one within 90% of the width (the old default, so 16:9 is unchanged), on 9:16 within the column the apps' buttons leave (0.62 centered, 0.7 on the column's own center), one off center within twice the room on its nearer side, so a long line wraps instead of running off. A width asked for is kept; titles already made keep theirs, so older projects draw the same; export_versions gives the titles it lays out again the new frame's width. A word wider than that still runs past it (check_project says so). Case (CapCut's Aa / AA / aa): shown as typed, UPPER, lower or Title, the typed words kept, on the canvas and in the inline editor alike.
Font weight (100 thin to 900 black): the Text tab's Weight list shows the weights the chosen font really has (each face it draws), so a heavy display line pairs with a light one; Bold is weight 700, and a weight wins over it (style.weight, ADR-071).
Animated size, spacing and color (ADR-071): a title's size, letter spacing and color keyframe (the diamonds beside Size, Spacing and Color), so a tracking expand, a grow or a color change plays; a left-aligned title keeps its left edge as it grows, a right-aligned one its right (animate_text_style, or add_keyframe on style.size and style.letterSpacing).
Enter splits a caption at the caret while editing it on the canvas (CapCut's): the second half starts where its first word is spoken (or as far in as the characters go, untimed), each half keeps its words' timings, typing goes on in the second, and it is one undo step.
Caption looks (CapCut's caption templates, Resolve 20's subtitle styles): the Captions tab offers Classic, Bold yellow, Boxed, Word pop (capitals with the spoken word highlighted), Neon and Minimal, each previewed on its card; one click restyles and places every caption, words and timings kept (set_caption_look). On a tall canvas a look, and add_captions' default style, is sized by the short side: a caption has the same pixels on 1080x1920 as on 1920x1080, instead of growing with the height to a dozen letters a line (a size asked for is kept). The same command moves, sizes and narrows every caption at once (y, x, size, maxWidth, and any other style field), over a look or on its own (ADR-124).
Saved styles (CapCut's Save as preset for text, Premiere's Text Styles): Text tab > Saved styles keeps a title's whole look under a name, in this viewer's storage so it is there in every project; a chip with a sample gives it to the selected title in one click, words kept.
Preview a new title: a title, template or sticker added at the playhead plays its In animation once, silently, then returns to the original playhead. Reduced motion skips the preview. Pausing the preview cancels it without a later jump back ([[ADR-047 A new title shows by playing its In animation]]).
Fonts: the built-in list, Import font… (TTF, OTF, WOFF; kept per viewer and loaded at startup, so preview, export and headless renders draw it) and Installed fonts (the computer's families through Local Font Access, asked once). A project whose font is missing here says so in the picker and falls back to the system font.
Word art: 16 looks (neon, retro, comic, hollow, gold, fire, frost, candy, die-cut, chromatic, typewriter, highlight...) from fill, stroke, shadow and box combinations. Click with text selected (or drop on a text clip) to restyle it, keeping its words, size and layout.
Templates: 12 animated title designs — name and title, name tag, subscribe callout, chapter title, quote card, countdown, location tag, big opener, news banner, social handle, end card, link in bio — built from text and box layers with staggered in/out/loop animations, each layer its own clip ([[ADR-025 Stickers and templates are ordinary clips]]). Agents: add_text_template (with replacement words) and apply_word_art.
New text lands above everything showing at that time, and never on a footage row (a B-roll row stays B-roll). A multi-layer template lands as one block of Text rows directly above the footage: overlapping layers stacked in order, layers that follow one another on one row; a later template reuses the same rows; its layers are grouped, so they select and move together (Alt+click picks one).
Animation presets preview on pick, as in CapCut: choosing an In plays the clip from its start to where the In settles, an Out to the clip's last frame, a loop one cycle, once and silently. Each tile shows the motion: the layer settled and a dashed ghost where it starts (In), ends (Out) or swings to (loops), titles' per-letter, word and line presets as units part-way; the tile plays on hover.
Type on the canvas, as in CapCut: double-click a title or caption in the viewer or on the timeline (or press Enter with it selected) and a caret appears in the rendered text with everything selected; the frame redraws as you type, in the real style. Escape or a click outside finishes, and the whole session is one undo step. Enter breaks a title's line; in a caption it finishes and Ctrl+Enter breaks the line. Shortcuts stay off while typing ([[ADR-030 The canvas text editor is a transparent textarea over the engine's text]], [[ADR-031 Typing into a text clip is one live session]]).
The inspector's Text box is live too, and mirrors typing on the canvas.
Spoken-word highlight (a caption's Text tab > Spoken word, CapCut's caption highlight): the word being said draws in its own color. Auto captions keep each word's start time (wordTimes), trims and splits carry them, and an edited caption whose word count changed simply stops highlighting. add_captions takes words; set_text takes highlight.
Text to speech on this machine (Text tab > Text to speech, as in CapCut): thirteen English voices from Kokoro-82M (Apache-2.0), Slow/ Normal/Fast and Best or Draft quality; the voice lands on an audio track at the title's start, one undo step with its speech file. The first voice downloads the model once: 325 MB at Best (full precision, on WebGPU or the CPU), 92 MB at Draft (8-bit) ([[ADR-050 Text to speech runs Kokoro on the user's machine]], [[ADR-084 Voiceover is read at full precision and finished like a recording]]).
Natural voice (every voice the app makes; [[Natural voiceover 2026-10-19]]): read whole, a sentence at a time, at a narrator's speed (0.95); pauses at commas and sentence ends lengthened to a reader's (0.28 s, 0.55 s); a line the voice rushed read again slower; a low cut and a little presence; every line at one loudness; quiet room tone under the pauses instead of digital silence; faded edges; the voice compressor and a touch of room on the clip. finish: clean or raw for less.
Voiceover from a script, directed (agents: add_voiceover): every line read and laid one after another at its real length on a new Voiceover track, with a caption per line timed to its voice, as one undo step with its speech files (undo leaves nothing in the library). Each line can have its own voice (several speakers in one call; blends such as af_heart:70,af_bella:30), speed, time (at, on a beat or a cut) and pause after; the gap after a line otherwise follows its ending (a comma runs on, a sentence rests, a paragraph rests longer). Pauses inside a line are written in it ([pause 0.4], [beat], <break time="0.4s"/>) and lengthen the voice's own pause there, so the sentence keeps its intonation; captions never show them. pronounce respells names and acronyms for the voice while captions keep the words ([[ADR-083 Voiceover lines are directed in the script and keep it]]). Each line lands on a pace: a narrator's 2.3-2.8 words a second (or an ad's, a social video's, or as asked), its speed chosen by reading and measuring it, never by stretching the audio; its pause marks are out of the pace, a band asked is held over a slow or fast pace, and a slow line reads no faster than the voice's own speed ([[ADR-104 Voice and sound an agent can trust without ears]]). A word cannot be marked for emphasis: the voice model has no such control, measured ([[ADR-096 A voice's pace, a song's grid and a mix's balance are measured where they apply]]).
Listen back (agents: review_voiceover): Whisper hears each line and it is compared with the script word by word; each line's pace (words and syllables a second over its speech and over its clip, judged against the pace it was read to), silences, longest pause, loudness, true peak, pitch range and margin over the music (that line alone) are measured, with a verdict, the tool calls that fix what fails, and advice that does not fail it. A line that differs from its script is heard again by a larger Whisper (small) before the voice is blamed: what only the first one misheard needs no retake, and each difference says whether the recognizer or the voice is likely wrong. A misread word gets a respelling as it sounds ("does" "duz", "home" "hohm"), or a slower read and the advice to reword when it was respelled already; never a placeholder. A line marked pace: slow (an end-card tagline) is not flagged as slow ([[ADR-092 A voice's known script decides its words, a second hearing decides who misheard]]).
Retake one line (agents: retake_voiceover): new words, a voice, a speed or a pronunciation, read and put in the line's place; its caption follows, the old take leaves the library, and ripple moves the lines after it; one undo step.
Voices to cast (list_catalog section voices): each voice's accent, gender, its author's grade, character (measured pitch, melody and pace) and what it suits, the most natural first.
Auto captions on this machine (Whisper, [[ADR-007 Auto captions run Whisper on the user's machine]]): no upload, no limit; readable line breaks, or one word at a time (CapCut's short-form style); caption list editing; apply style to all; SRT/VTT import and export. A voice read from a script (a voiceover line, text to speech) is captioned in its script's words, timed by what Whisper heard, so a synthetic voice's "All of it, home" is no longer "Olivet Helmed"; the transcript of a whole take says its script too ([[ADR-092 A voice's known script decides its words, a second hearing decides who misheard]]).
Find and replace in captions (Captions tab; CapCut's; replace_caption_text): fix a misheard name everywhere, whole words and case as chosen, with a live match count; titles are left alone.
Edit by transcript (Captions tab; Premiere's Text-Based Editing): the selected clip's track as text, clip by clip; select words and press Delete to cut them with the pause around them, gaps closed, one undo step; click a word to go there; the word under the playhead lights up. Pieces of a cut clip read on without hearing it again. Agents: get_transcript then cut_ranges. The words are kept for the session, not in the project; clips with a speed curve or reversed are left out.

Generated music

An original, royalty-free score made on this computer, for agents first and in the Audio tab's Generate music card ([[ADR-085 Music is composed and synthesized in the app, seeded and offline]], [[ADR-086 A score fits an edit by whole bars and a nudged tempo]], [[Music generation 2026-10-19]]). Nothing is downloaded or sampled; the same arguments and seed give the same music.

Five styles: product launch (four on the floor, a pumping supersaw pad, sub and offbeat bass, a 16th arp, a bright hook), cinematic (string ostinato, legato strings, horns and choir, taiko and toms, braams and hits, a long hall), upbeat corporate (piano eighths, a plucked guitar strum, glockenspiel, claps and shaker, an eighth-note bass), lo-fi chill (a swung boom-bap, Rhodes sevenths and ninths, a round bass on the kick, vinyl and tape wow) and ambient (evolving pads, glass bells, a tonic drone, a soft pulse).
Composed, not looped: each style's chord progressions in any key and mode, voice-led bar to bar; a four-bar hook in key that repeats in every drop and is teased in the intro and breakdown; drums with velocity, swing and fills into each change; risers, reverse cymbals, impacts and a beat of silence into drops; sidechain pumping; breakdowns that thin out; a final hit that rings out (or a hard stop).
Mixed and mastered: stereo width with a mono low end, convolution reverb sends, a ping-pong delay on the lead, each stem's loudness set to the style's balance, then a glue compressor and a true-peak limiter to -14 LUFS (or any target) under -1 dBTP. Brightness (agents: brightness, -1..1) tilts the master about 1 kHz (at 1 the highs 6 dB up from 3 kHz and the lows 3 dB down under 300 Hz), darker under a busy voice or brighter for a launch, the loudness and true peak held; the launch style leans bright by default (0.4), as its measurements against the hand-made track it imitates asked.
Fits the edit: a length, or sections with bars, seconds or fixed times (a drop at 8.0 s, an outro ending at 56 s); the tempo moves a little so they land on bar lines, and the answer says how each fit.
A cue sheet: tempo, key, chords, every bar and beat, the sections, drops, the final hit, cut points, and Bar, section and Drop markers on request, so cut_to_beats and add_beat_hits work on it at once.
Stems: drums, bass, harmony and lead as files of their own (they add up to the mix), on four grouped tracks if asked.
One section again: a section's own seed regenerates its drums, fills and touches and leaves the rest note for note.

Epic edits

Music-synced montages (hype, velocity and AMV edits, CapCut's beat-synced templates done by hand) for agents first: each is a command or MCP tool, so a model makes a whole edit in a dozen calls (scripts/drive/epic-edit.js makes a 13 s one). Times are timeline seconds.

Read the music (analyze_music; Final Cut's beat grid is the model): tempo, every beat, downbeats (bars of four), phrases (four bars), sections named intro, verse, build, drop, breakdown or outro with their energy, each beat's loudness, strong hits on or off the beat, and the drop, as data in timeline seconds, and as Beat, Bar, Phrase, section and Drop markers when asked ([[AI tools]]). The markers follow the music clip: trimmed, moved, split or sped up, they stay on the song's beats, and reading again replaces them; the tempo answered is the one heard.
Give the song's grid (set_music_grid): when the reading is wrong (bars between the kicks, a drop missed), its tempo, a bar's first beat and its parts, kept with the file; every later reading, mark_beats and check_project use it, and its markers are placed at once ([[ADR-101 A song's markers follow its clip, its grid can be given, and designed layouts refit as designed]]). A person gives and corrects it in the Audio tab's Beat grid: Detect keeps the reading as one fitted tempo and downbeat, drawn on the clip as beat dots and bar lines; the tempo typed or tapped, the downbeat nudged 10 ms or set at the playhead, parts added on the bar nearest the playhead, each through set_music_grid ([[ADR-119 A person corrects a song's grid and cuts its bars, markers say what they follow, and the check hears its joins]]).
Cut to the beat (cut_to_beats): a list of shots laid end to end on the main track, every cut on a beat, bar or phrase (or the agent's own times): N beats a shot, a pattern such as 4, 4, 2, 2, 1, 1 that speeds up, or a shot's own count. One long clip gives many shots (each reads on from where the last stopped); a source window past the file's end slides back, and a file too short for its slot ends on an earlier beat.
Hits on the beat (add_beat_hits): flash (blown out to white), zoom punch, camera shake, RGB split, glow or zoom blur, several as one hit, on beats, bars, the main track's cuts or given times. Each is a short adjustment layer on a Hits track (above the footage, below bars and titles) whose effects peak on the beat and ease out, keyframed, so preview and export match and the user can retime or delete any of them. Flashes keep to three a second (WCAG 2.3.1): a beat that would break it keeps its other effects.
Cinematic bars (add_cinematic_bars): letterbox to 2.39, 2.35, 2 or 1.85:1 on any canvas (pillarbox when the canvas is wider), sliding in and out if asked; an adjustment layer with the Letterbox effect on a Bars track, under the titles. New titles and media never land on a track of adjustment layers.
Speed ramp on the beat (set_speed_ramp, velocity edits): a shot's slow moment (or fast one) lands exactly on a beat while the shot keeps its place and length, so the cuts stay on the beat; the ramp reads more of the media instead. A speed curve preset can be aligned the same way.
Fit the music (fit_music): slide a song so its drop lands where the cut wants it (its markers move along), then end it with the picture, on the last beat or bar, or at a time, faded out; optionally cut the picture there too.
Moves and sound: Whip pan left and right, Zoom punch and Spin blur transitions (motion-blurred, so the cut hides in the move), and add_sound_effect's end_at, so a riser or reverse cymbal peaks on the drop.

AI tools (all on this machine)

Remove silences, Split scenes, Beat markers, Normalize loudness (EBU R128, to −14/−16/−23/−24 LUFS, the true peak under its ceiling, −2 dBTP for ATSC's −24; spec names one; a mono clip is measured as it plays through the mix's equal-power center pan, -3 dB each side) and Auto ducking (music dips under speech as editable volume keyframes) and Stabilize (Video > Basic, as in CapCut, or the AI tools card: three levels, translation only, measured on this computer) and Reduce noise (a spectral gate for steady hiss and hum; the clip plays a cleaned copy, a video's sound extracted first) in the library's AI tools tab, one undo step each ([[AI tools]]).
Auto reframe (CapCut's and Premiere's; AI tools card, auto_reframe): into 9:16, 1:1 or 4:5, the canvas reshaped and the clip filling it with position keyframes that keep its subject centered as it moves; or from a box, with Tracking > Keep subject centered.
Tracking (CapCut's, in the layer's Animation tab; track_motion): pin a title, sticker or picture to a moving subject in the video under it. A box placed on the viewer is followed from the playhead on this computer and the layer gets position keyframes, a handful, editable like any others ([[ADR-054 Tracking writes position keyframes]]).
Sync audio by waveform (CapCut's Sync video and audio, Resolve's Auto Sync Audio > Based on Waveform; sync_audio): select a separately recorded sound (a lav, a recorder) and its video, right-click, and "Sync audio by waveform" (or "Sync audio and mute camera sound") matches the two sounds' onsets on this computer and moves the audio clip into sync, exact to the sample, one undo step. Sound from before the camera rolled is trimmed off the head; unrelated sounds are refused. Also an AI tools card; sync_to_clip places a clip by a known offset ([[AI tools]]).
Remove filler words (CapCut's and Premiere's; AI tools card, remove_filler_words): Whisper base or small on this computer transcribes the clip and its "um", "hmm" and "ah" are cut with the hesitation around each, the gaps closed. Whisper does not transcribe "uh" or "er", so those stay ([[Filler words]]).
Remove background (CapCut's Video > Remove BG > Auto removal, also an AI tools card): a segmentation model on this computer cuts the person or main subject out of every frame, once, with progress and cancel; the clip then plays and exports over the tracks below in real time. Off keeps the matte, so On again is instant. ormbg on WebGPU, MediaPipe Selfie on WASM, both Apache-2.0, downloaded on first use ([[ADR-032 Remove BG runs ormbg on WebGPU, MediaPipe on WASM]], [[ADR-033 Mattes are made once and stored as grayscale video]]). Chroma key sits under it on the same sub-tab.
AI assistant (called Copilot until 2026-10-17, renamed because Microsoft and GitHub use the name): ask for an edit in words; a model on this computer (Ollama or LM Studio) applies it with the editing commands, undoable as a whole. It docks as a resizable full-height column the editor makes room for, like Premiere's side panels, instead of covering the inspector and the timeline's zoom; the library steps aside in a window too narrow for four columns ([[ADR-064 The AI assistant docks as a column the editor makes room for]]). The composer grows to five lines, sends on Enter, and shows the steps as they run with a Stop; failed requests can be tried again, and a stopped or failed turn's edits stay undoable as one. Offline, it says whether the server is not answering or has no model that can call tools.
Connect agents (desktop, the AI assistant's second tab): after Allow AI agents, Add to Codex and Add to Claude Code run that CLI's own mcp add for the stdio bridge, reporting added, already added (never replaced), not found (with its install guide) or the CLI's error; the ready-made codex mcp add and claude mcp add lines and a Codex config.toml entry are there to copy ([[ADR-065 One-click agent setup runs the agent's own CLI]], [[Automation]]).

Sound design and delivery

Effects (Audio tab, under Compressor; set_audio_filter, set_reverb, set_echo, set_tape_stop): the trailer and epic-edit moves on any video or audio clip, built into the clip's one Web Audio chain, so preview and export sound the same ([[ADR-060 Sound design rings past the clip and is measured as exported]]).
- Low-pass and high-pass, 24 dB per octave, resonance 0 to 24 dB. The cutoff keys like any slider (a log slider, typed in Hz) and moves between keys on a log scale, the same octaves each second; the agent's sweep writes the two keys of the "muffled build, open on the drop" in one call.
- Reverb: Room, Hall or Cathedral, then mix, decay (RT60) and size. A convolution reverb whose impulse response is made here from those numbers (seeded noise, unit energy, highs dying first), mixed at equal power so the clip stays as loud.
- Echo: delay time, feedback (repeats), mix.
- Tape stop: the sound slows to a stop over the clip's last seconds, its pitch falling with it (speed falls linearly, a turntable coasting; the level follows the speed under half speed). Only the sound: a video's picture plays on. A split keeps it on the part with the end.
- Echo and reverb come after the clip's volume, so their tails ring on past the clip's end and its fade (Premiere cuts clip-effect tails at the edit); export windows start early by the longest tail, so a reverb rings across them too. The keyframe panel lists the cutoffs and the two mixes; Paste Attributes copies the effects with the sound.
Loudness report (measure_loudness): the mix measured as export renders it, effects and tails included: integrated loudness (BS.1770), loudness range (EBU Tech 3342), the loudest 3 s and 400 ms, true peak (4x oversampled, BS.1770-4 Annex 2) and sample peak, with pass or fail and the reasons against online (-14 LUFS, -1 dBTP), EBU R128 (-23, -1 dBTP) or ATSC A/85 (-24 LKFS, -2 dBTP). It flags a mix that passes full scale, and measures as export with a target would deliver it, so an agent checks before it exports ([[ADR-061 Delivery holds the true peak and says whether it passes]]).
Broadcast targets: export Loudness and Normalize loudness offer -24 LKFS (ATSC A/85, US TV) beside -14, -16 and -23; the limiter holds the true peak, not the sample peak, under -1 dBTP (-2 for ATSC), and the export's answer says what the mix reached.

Ads and deliverables

Kinetic typography (After Effects' text animators, CapCut's per-character text animations): a title's in, out or loop animation can play by each letter, word or line, with a stagger (0 all together, 1 one after another) and an order (first to last, last to first, from the center, random, the same on every render). Presets: Typewriter (letters typed behind a caret; as an out it deletes from the end), Letter rise, Letter fade, Word pop, Word rise, Word slide, Line rise, and two sweeps, Highlight (a marker box drawn behind the words) and Underline, in the title's accent color; a finished sweep stays drawn. Any other animation moves per unit too (Rise by word, Float by letter is a wave). The rasterizer draws each unit, so the viewer and the export agree; the Animation tab lists the presets for titles only and adds Moves by, Stagger and Order (set_animation unit, stagger, order).
Ad looks for titles: a glow (neon, three strengths), a gradient fill (two colors at an angle) and a second outline (sticker style), in the Text tab and in every text style an agent sends.
Brand kit (kept in the project; Details > Brand, set_brand): primary, secondary, accent, background and text colors, a heading and a body font (two families at most), logo pictures by variant (main, light for dark backgrounds, dark for light ones, icon), the brand's name, website and tagline. Titles take a role from it (add_text role: headline about 9% of the frame high with a shadow, subhead, body, label, a pill button, a badge), and apply_brand restyles existing titles and solids. Labels on a fill pick white or near-black by WCAG contrast.
Ad elements (add_ad_element), each one call, built from ordinary clips in the brand's colors, grouped, inside the 90% title-safe area (on 9:16 clear of the apps' buttons and captions): an end card (logo, headline typed in by word, a pulsing call-to-action button, the website), a lower third (name in a box over the title in the primary color), an offer badge (tilted, pulsing, with a small tag), a call-to-action button, and a logo reveal (the logo pops in, with an optional glow flare and white flash, and the tagline).
Text behind the subject (text_behind_subject): a title sits behind the person or product in a video or a photo. The background is removed on this computer (a video's Remove background matte; a photo cut out once into a new picture with transparency) for a copy on a track above the title, silent and grouped with the original; one undo step. The copy takes the grade of an adjustment layer it sits above, and a version whose shape lets the subject hide the title shows the title in front ([[ADR-103 Checks see inside compounds, and versions refit cards, scrims and titles as the check judges them]]).
Deliverables (export_versions): a campaign's versions in one call (a group, such as an ad element, moves and scales as one unit, anchored where it sat; [[ADR-063 Versions fit a group as one unit]]), each its own file: 16:9, 9:16, 1:1 and 4:5, 30/15/6 s cut-downs (the opening and the end card kept, the middle cut, the music fading at the new end) and a textless master (titles and captions off). Footage that fills the frame keeps filling it, or fits over a blurred copy of itself; titles, logos and badges keep their size against the short side and move inside the new frame's safe area. Hand-animated films adapt too: layers are placed where they rest and their keyed motion is laid out again around it, a window compound sliding in from off the edge still does on 9:16, and a one-word wordmark too wide to wrap shrinks to the safe width ([[ADR-067 Versions lay keyframed motion out again around its rest]]). A tall version of a wide film stacks what stood side by side: a window above the headline beside it, a split screen's halves one above the other (cut again wider), each as wide as the safe column, a label or a glow on a window moving with it; a square version moves each such pair as one group. Captions are burned in on tall versions by default (even from a hidden caption track), sized by the short side and kept clear of the stacks; captions says burn, none or as_project ([[ADR-091 Tall versions stack what stood side by side]]). A title card built as a compound refits as one picture, a split screen whose halves filled the frame fills the new one, text never ends under the frame's readable size, and overrides move, resize or hide a clip in one version by hand, kept in a saved version project (ADR-101). The versions are built from the master as separate documents, so the project in the editor never changes; check answers one contact sheet of them all first (check_at picks the moments). Seven 480p versions of a 5 s ad took 4.4 s headless. A shot fitted with bands (a widescreen screen recording in a 9:16 master) is footage a version reframes, at its pixels against the short side and covering the new frame; focus points with at make a path; every answer says what became of focus, pushes and overrides (options), an override on a shot carries its rings, and footage left floating small is named (coverage) ([[ADR-123 Fitted shots are footage a version reframes, and framing knobs act or say why]]).
A whole ad through MCP alone: scripts/drive/ad-spot.js makes a 15 s spot with 27 tool calls (brand, push-in, kinetic headline, title behind the roaster, lower third, offer, end card, faded music), checks it on a contact sheet and exports 16:9, a 6 s 9:16 cut-down and 1:1.

Export

CapCut's export dialog: MP4/MOV/WebM/MKV, H.264/HEVC/VP9/AV1 by what the device can encode, 480p to 4K, quality levels or a bitrate, frame rate, in/out range, audio-only (AAC in M4A, MP3, WAV) and still frames.
MP3 (audio only, and the Audio only (MP3) preset): 256 kbps, 48 kHz stereo, encoded by LAME in WebAssembly (@mediabunny/mp3-encoder), loaded by the first MP3 export, on the desktop and the web alike; export_video format mp3 (or m4a, wav) for agents.
Captions on export (the dialog's Captions row, shown when the project has captions; export_video captions; Premiere's burn-in or sidecar): Burn into the picture (the default), SRT file beside it with the picture left clean, both, or leave them out. The SRT is timed to the exported range (an In-to-Out export starts at 0). The desktop app saves <name>.srt beside the export; the web build downloads it. Agents get its path as captions_file ([[ADR-080 MP3 by LAME in WebAssembly, captions leave an export four ways]]).
Save frame as PNG from the player (the camera button, File menu, Mod+Shift+E, Premiere's Export Frame key): the frame under the playhead at the project's size, without the export dialog.
Frame-exact and sample-synced (the export drive reads the framecode back); a canceled export never leaves a partial file.
Loudness (Audio > Loudness; Premiere's Loudness Normalization): bring the mix to -14, -16, -23 or -24 LUFS. A first pass measures the whole mix (BS.1770) and its true peaks, then it is rendered through the gain that meets the target, with a limiter holding the raised true peaks under -1 dBTP, -2 for ATSC's -24 (up to 6 dB of limiting; the whole mix is known, so it looks ahead for free). The result notes what it measured, what it reached and how much the limiter held: reaching the target shows as success (green, a check); a mix held short of it is a warning, with how far under it landed. Gain alone stopped the RacePulse promo at -17 LUFS of -14; with the limiter it measures -14.3 in ffmpeg, peaks at -0.9 dBTP.
Presets at the top of the dialog: YouTube 1080p and 4K, TikTok, Reels and Shorts, Small file (720p), High quality master (HEVC), Animated GIF and Audio only (WAV); changed settings read Custom and can be saved under a name (per viewer) and deleted. TikTok, Reels and Shorts is made for 9:16: it is never named for a canvas of another shape, and picked there it says what will export (16:9 stays 1920×1080) and offers Make the canvas 9:16, which only that click does, as one undo step. A codec the device cannot encode at that size gives way to one it can, and the dialog names both. In to Out, with no marks, is shown disabled with the reason under it.
Animated GIF (Format: GIF, or the Animated GIF preset): the same frames the video export draws, 256 colors per frame (gifenc), 10 to 25 fps with delays that add up to the real duration, silent, up to 720p and 60 seconds (it is built in memory). The GIF drive reads every frame back against the framecode fixture.
Timeline as OpenTimelineIO (File > Export timeline): tracks, gaps, transitions, speed, titles, compound clips (nested stacks) and markers for DaVinci Resolve, Premiere's OTIO plugin and other editors ([[ADR-034 Timelines leave as OpenTimelineIO]]).

Library

Sound effects in the Audio tab (CapCut's is a cloud library; Resolve ships a local one): Whoosh, Swish, Pop, Click, Ding, Success, Riser and Boom, and for epic edits Impact, Sub drop, Braam, Reverse cymbal, Glitch, Camera shutter and Swoosh up, synthesized on this computer from sines, saws and seeded noise, so they are the same everywhere and nobody's license applies. The card's play button auditions one; double-click, + or a drag adds it on an audio track, the WAV made once per project and reused (add_sound_effect for agents).
Solid color in the Adjustment tab (CapCut's color background): a white layer on a new top track at the playhead, its color set in the inspector; drag it to place it.
CapCut's tabs: Media, Audio, Text, Stickers, Effects, Transitions, Captions, Filters, Adjustment, with category sub-navigation; then AI tools, Markers and Check.
Check (also File > Check project, and the Export dialog's Check row): the agent's check_project, run for a person on request, with the same measuring (each title's contrast on the rendered picture, the sound's last seconds), progress and Cancel. What is made (General video, Ad, Social short, Cut to music) picks the rules. Findings are grouped as text, timing and sound with counts, each in plain words with the control that fixes it; clicking one moves the playhead to it, selects its clip and opens the inspector tab with the fix. An edit marks the check out of date; Export shows the last check's counts and leads to it, without blocking the export ([[ADR-111 A person checks the project, Space presses what the keyboard reached, and a transition on sound crossfades]]). It hears where audio clips meet (each join on its own track, up to 24): a tick, dropout or click, or a sound cut off, with the clip menu's crossfade as the fix ([[ADR-119 A person corrects a song's grid and cuts its bars, markers say what they follow, and the check hears its joins]]).
Previews drawn by the engine: filter, effect, transition and text cards show the real shaders and text rasterizer on a generated sample shot, or on the selected clip's own frame; effects, transitions and titles play a loop on hover (a still under reduced motion). Rendered lazily for visible cards, one at a time, cached ([[ADR-026 Library previews are drawn by the engine]]).

Stickers

A local sticker library: about 140 stickers in ten categories with search — emoji drawn from the system's color emoji font, and original graphics drawn in code (curved and scribble arrows, marker circles, underlines, highlighter, bubbles, comic bursts, subscribe/like/follow style badges, stars, hearts, checks). Nothing is downloaded.
Click + or drag onto the timeline: the sticker lands above everything at that time at about a third of the frame, with a pop-in and a gentle loop (the tab's motion menu; per viewer). It is an ordinary image clip, so transform, blend, masks and animations all apply ([[ADR-025 Stickers and templates are ordinary clips]]).
Rendered once to a PNG asset per project; adding the same sticker again reuses it, and stickers stay out of the Media tab.
Agents: add_sticker by id, label or the emoji itself, with position, scale, duration and motion; window.videoEditor.stickers() lists them.

Keyboard

CapCut's in-app shortcut list, Premiere's where CapCut has none (src/lib/keymap.ts); a searchable shortcuts panel; tooltips show each button's chord, read from the keymap.
Space presses a button, switch, checkbox, tab or menu item reached with the keyboard, as on the web; from the page, the timeline, the viewer, a slider, or a button a click left focused, it plays (ADR-111).
Custom shortcuts, as in Premiere's Keyboard Shortcuts: Change on any row and press the new keys; a chord another action uses is named and moves only on Replace. Remove, per-row reset and Reset all; changes are per viewer and survive restarts.

Automation

Three doors, one engine ([[Automation]]):

Headless render: openframe --render project.json --out file, JSON-line progress, exit codes.
MCP for agents (opt-in, token-locked, local only): every editing command plus preview_frame and preview_frames (a contact sheet, JPEG so it stays under what MCP clients pass a model; as PNG, clients re-encoded big sheets with 256 colors and skies banded) so an agent can look at its work, list_projects, open_project and new_project to move between projects as the home screen does, and export_video / export_status to make the file; HTTP or --mcp-stdio. A model learns the tools from the help tool, three MCP prompts (make an ad, an epic edit, a short) with design rules, guide resources and a full list_catalog; [[MCP tools]] is the generated reference. Edits answer with only what they changed; batch runs many as one undo step; frame_region zooms a shot onto a rectangle of its picture, still or moving ([[ADR-052 Agents read what changed and export without a dialog]]), through any number of moves in one call (moves, ADR-120), each region centered on any canvas point at any zoom with place_at (ADR-123). Every answer names the tool set it came from, so the stdio bridge tells a connected client (notifications/tools/list_changed) when a newer build brings other tools; over HTTP the client reconnects ([[Automation]]).
window.videoEditor in the page: commands, actions, import, render, pixels, animated values (paramAt) and the AI tools — what the drives use.
Keyframe commands: add_keyframe, move_keyframe, set_keyframe_ease and remove_keyframes, with one ease vocabulary (twelve presets or a bezier). add_keyframe refuses a path that does not animate on the clip, naming the ones that do, and describe_project shows every key as [at, value, ease], so edits to keys show in answers ([[ADR-066 Keyframes are refused where nothing moves and shown in answers]]).
Answers stay small as a project grows: compounds are answered only when they change, summed up; open_project and new_project answer a summary; add_sound_effect places a list of sounds in one call and one undo step.
check_project measures what it judges: each title's WCAG contrast with the rendered picture behind it, a music clip's last second, and the shots on the busiest picture track ([[ADR-068 check_project measures the picture and the sound it judges]]); an audio clip cut off before the end while it still sounds, with no fade, is a warning (sound_cut_off, ADR-100); so is a hole, a click or a sound cut off where two audio clips meet, each join played on its own track (click_at_join, sound_cut_at_join, ADR-119).
Workflow commands: relink_media, remove_media, edit_media_folder, organize_media, apply_effect_preset, paste_attributes.
Layout commands: align_clips (with a margin, so titles of any width share one left edge inside the safe area), distribute_clips, set_crop (edges as source fractions, or the largest centered crop of a ratio) and set_mask (any shape and number, or none).
Preview prepares long-GOP video before cuts and transition handles, with adaptive lead time and a bounded admission estimate (ADR-074). Clips larger than the preparation budget still decode on demand.
Music analysis reports every detected drop as well as the biggest, and supports short two-bar sections and breakdowns.
Loudness reports can include isolated audio tracks and Voiceover-to-music balance. Ducking can target a measured LU difference, returning the achieved result and editable keys rather than only taking a fixed depth.

Icon consistency

The toolbar uses drawn icons for every trim tool and timeline Fit. Reset is counterclockwise; Rotate is clockwise. The assistant uses Bot, automatic tools use WandSparkles, and effects use Sparkles. Track icons reflect their contents, including pictures, captions, stickers, shapes and adjustment layers. Empty results include an icon, title and next-step hint. See [[Icons]] for the mapping.

Compact layouts and keyboard controls

Library tabs lay out in balanced rows (all twelve in one row at 2560 px, six and six below), keeping every destination visible; where labels would need a third row or a quarter of a short panel, the tabs show icons alone, named by tooltips (src/lib/libraryLayout.ts). Below 300 px the catalog categories move above the cards as wrapping chips, so cards keep two columns. The media browser's folder filter sits with the others and Favorites only is a heart toggle beside the views; AI tool cards tile two across in a wide library. Details ratios and canvas dimensions fit the narrow inspector; text style, case and audio channel choices wrap between whole buttons. Segmented radio controls support arrow keys, Home and End with one tab stop. Fit, Fill and Stretch share an inset button group.

Home thumbnails draw hover and keyboard focus rings over their images, project names have styled tooltips, and preset cards align their image and text rows. Track headers show their names with ellipsis and a tooltip when space is short. Marker editing preserves a multi-row list. Shortcut search keeps the dialog size stable. The keyframe dock reserves room to scroll the timeline's tracks.

Narrow viewers keep current and total frame-exact timecodes on a compact row. Toasts appear at the bottom, clear of Guides. Toolbar Split and trims reflect whether an unlocked clip can be edited at the playhead. Add marker remains available on empty timelines and at existing markers because both are valid operations. Mirror and Rotate use the shared edit boundary. Title-bar project renaming accepts at most 120 characters, matching Home.

Inline title styling

In the text inspector, expand Style range, choose a word, and set its color or weight. Clear word style restores that word to the title style. Agents can use style_text_range with character offsets or a literal match, including all occurrences, to apply color, gradient, weight, italic, underline, or size scale. Ranges use UTF-16 offsets with an exclusive end. Typing shifts and trims ranges; inserted characters inside a range inherit it. Run colors override animated base color. Preview, alignment, text checks and version exports use the same run-aware raster layout.

Layout presets

Select two to four overlapping pictures and open Layouts in the inspector. A picture on the main track stays there (in picture in picture it must be the full-frame one), so the timeline never ripples; the others stack above it on Layout tracks. Tiles offer side-by-side, stacked, grid, triptych (three pictures), and picture-in-picture arrangements. Fill (the default) crops each picture to its cell; Fit shows the whole picture centered in it, for screen recordings (fit: "contain", with background filling the cell behind it as an editable shape). The Layout tracks go directly above the highest of the chosen clips' tracks, so labels already above them stay on top. apply_layout also accepts gap and margin (fractions of the shorter canvas side), rounded mask radius, editable border shapes, and a slide or scale entrance. Clips are placed in input order, with the first PIP picture full frame. Layout replaces position, scale, rotation, crop, mask and their keys, plus clip animations, canvas fill, edge repetition and wiggle. Other effects remain. The whole layout is one undo step. Borders are separate shapes grouped with their pictures; remove an old border before applying another bordered layout.

Group transforms

A multi-selection has one viewer box: drag it to move, use a corner to scale the arrangement, or the rotation handle to rotate it about its combined center. Each gesture is one undo step. transform_group accepts a group_id or explicit clip_ids, canvas-fraction x/y offsets, a scale multiplier and a rotation offset in degrees. Add at in timeline seconds to key every visual member using its own clip-relative time. Existing keys are preserved; audio members remain unchanged. Without at, geometry is evaluated at the latest member start and existing keyed paths receive keys there. Times outside a member clamp to that member’s span.

Motion path points

Select a picture with position keyframes to see its motion path. Drag a dot to move that key position; the gesture is one undo step. A focused dot can also move one canvas pixel with an arrow key. The move_motion_point command takes a clip id, an existing key time in timeline seconds, and x/y positions in canvas fractions from center. Both axes receive a key at that time, with existing easing preserved.

Mixer, animated images, and timeline display

Audio track mixer: open Mixer from the timeline toolbar or View menu. Every audio track and visual track carrying audio has a dB fader, pan, mute, solo, and live post-fader peak/RMS readings. Master has a fader, stereo readings and the player's short-term LUFS. Dragging a fader or pan makes one undo step; double-click resets it. Master gain is included in preview, offline loudness measurement and export. Commands: update_track, set_project (master_volume).
Animated GIF, WebP and APNG: when ImageDecoder supports the format, import reads real frame durations and retains alpha. The initial clip lasts one loop; extending it repeats the loop. Timeline thumbnails, library hover scrub, player and export share these frames. Platforms without ImageDecoder use their still-image decoder. A decoded loop over 256 MiB is refused with a readable error (ADR-089).
Timeline display: the toolbar's display menu remembers waveforms, video thumbnails, clip names, and small/medium/large track height per browser profile. Track header color swatches use the clip-label palette; a clip's own label wins. update_track.color sets or clears a track tint.

Portable project files

File > Collect files on desktop creates a new folder inside the chosen folder, with project.json and a media folder. Originals, proxies, LUTs, and cutout files are copied once per distinct path; the JSON uses relative paths. Existing files are not overwritten. Progress reports completed files; missing or nonlocal sources fail the collection. On the web, this downloads JSON only and explains that media stays in the browser.

File > Open project file imports JSON through normalization with a fresh project id, preserving existing saved projects. Desktop resolves relative media beside the JSON. Missing media uses Manage media's existing relink workflow. On the web, browser media keys work in the same profile; files from another computer need relinking. Commands: collect_project (desktop only), open_project_file (optional absolute desktop path, otherwise picker). See ADR-090. Native dialogs and copying still need a desktop validation pass.

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Features.md

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Export

Library

Stickers

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Automation

Icon consistency

Compact layouts and keyboard controls

Inline title styling

Layout presets

Group transforms

Motion path points

Mixer, animated images, and timeline display

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Features

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Speed

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Epic edits

AI tools (all on this machine)

Sound design and delivery

Ads and deliverables

Export

Library

Stickers

Keyboard

Automation

Icon consistency

Compact layouts and keyboard controls

Inline title styling

Layout presets

Group transforms

Motion path points

Mixer, animated images, and timeline display

Portable project files