Propose timeline edits
Create reviewable clip edits that use the Editor’s existing undo history.
Interactive timeline mixer
Download Timeline mixer, or choose Timeline mixer template in the Block builder. Its complete interface lists video and audio clips with individual level sliders, live percentages, reset, empty-state guidance, and a Review mix action. It uses StillMade.render and StillMade.onAction; the isolated production function returns a typed edit proposal. Existing Editor permissions, conflict checks, review, and undo still apply. No account APIs or provider keys are exposed to its interface.
Import the package, run its fixture, and change a slider in Preview. To use real clips, add it to a Project Type after Editor and open its Step in a project with a timeline. Review the proposed levels before applying them. It edits up to 100 clips per invocation; the interface does not play or render the timeline. Download its source and SDK from the builder to modify the HTML, CSS, interface JavaScript, production function, and fixtures independently, then reimport.
A Block can return a timeline-edit output to propose changes to existing Editor clips. Declare permissions.project: ["context.timeline.read", "timeline.propose"] and an input {type:"timeline",context:"timeline",primary:true}. The output is {schemaVersion:1,title,timelineId,commands}. Copy timeline.activeTimelineId into timelineId. Each command is {collection,operation,before,values}: collection is clips or audioItems, and before is the exact unchanged target object from the input snapshot. Use at most 100 commands, with one command per target.
| Operation | Values | Behavior |
|---|---|---|
| move | {start: seconds} | Move an existing item; no silent ripple |
| trim | {trimStart: sourceSeconds, duration: timelineSeconds} | Trim within known source duration; variable-speed, frozen and looping clips defer to Editor |
| split | {at: timelineSeconds, newId: "unique-clip-id"} | Split into two source-aligned clips, at least 0.05 seconds from either edge |
| volume | {volume: 0..200} | Set the existing Editor volume percentage |
| mute | {muted: boolean} | Mute or unmute an existing item |
| remove | {} | Remove the timeline instance, preserving source media |
| grade | {lut, color} | Grade clips only; retain original media and timing |
Run the Block in a project, accept its result, and open the Editor's media panel. Timeline edits from Blocks displays a visual before/after strip and each target's values and applies all commands together using ordinary Editor undo history. Desktop and mobile use the same proposal contract. A changed target, different timeline version, locked track, source overrun, or new clip overlap rejects the proposal. The Block cannot set arbitrary fields, insert external URLs, run code inside playback, or silently write the timeline. Re-run it against current context after a conflict.
Download Quieter clips for a complete isolated JavaScript example with a realistic timeline fixture. The proposal type is a sink for Editor review; it is not interchangeable with a timeline snapshot.
Caption proposals
Use collection:"captions" with these commands:
| Operation | Before | Values |
|---|---|---|
| caption.add | null | {id,trackId,text,start,end} |
| caption.update | Exact existing caption object | {text,start,end} |
| remove | Exact existing caption object | {} |
Caption times are seconds with end greater than start; text must be nonempty and at most 5,000 characters. Adding uses an unused item ID and an unlocked existing caption track. The standard captions track is created if absent. New captions use StillMade's existing caption defaults; updating text or timing preserves the caption's styling. Reapplying an insertion rejects its duplicate ID. The host compares existing captions against their captured snapshots before update/removal.
Download Caption from text. This complete Block takes text plus a scoped timeline, chooses an unused caption ID, and proposes insertion without modifying the project. Its output connects to the Editor's proposal review. Add or run it after opening a timeline, then review its result in the Editor's media panel.
Timed captions and caption styling
Download Captions 2.0.0. This standalone, remixable Block converts a transcript into editable timeline captions. It owns phrase grouping, word timing and caption appearance, runs in the JavaScript sandbox, and returns ordinary timeline-edit proposals for review and Apply. It does not transcribe audio or spend execution credits.
The optional context binding { "type": "transcript", "context": "transcript", "required": false } requires context.transcript.read. At whole-project scope it supplies a copied {schemaVersion:1, words:[{text,start,end}], text, audioUrl?} from the saved voiceover when word timings exist. It is omitted when absent and for scene, shot or asset selections. URL metadata grants no media access. Explicitly connected transcript inputs remain separate from this fallback.
Captions uses a connected transcript first, then entered text, then the project's saved transcript. Text without word timings uses estimated timing, identified in the proposal title. Start offsets word times into the timeline. Duration zero keeps transcript timing; a positive duration clips the result to that interval. A proposal supports at most 100 lines and rejects longer results without silently truncating them. Existing captions stay intact and locked tracks reject Apply.
caption.add retains its required {id,trackId,text,start,end} values and also accepts these optional fields. Unknown fields and values outside these limits are rejected by the same SDK validator and host apply path:
| Field | Accepted values |
|---|---|
words | Up to 1,000 {text,start,end} entries, ordered by start, contained in the caption interval; nonempty text up to 5,000 characters, end at or after start |
font | Hanken Grotesk |
size | 8–200 |
color, highlightColor | Three- or six-digit hex color |
background | none or three- or six-digit hex color |
backgroundOpacity, backgroundPadding, backgroundRadius | 0–100 |
position | top, middle, or bottom followed by left, center, or right, separated by one space |
animation | none or fade |
The host fills omitted appearance values with its existing defaults, preserves provided styling and clones word timings before saving through ordinary edit history. Caption updates retain their existing {text,start,end} contract. Package source, MIT notices, lineage and three fixtures are retained in the canonical archive; validate, test and remix it using the public CLI.