Video Composition

Video composition is the process of assembling multiple video clips, images, audio tracks, text overlays, and graphical elements into a single rendered video output. It is the core capability that distinguishes the Video Editor from CE.SDK’s design-focused configurations. The defining ingredient is the time axis: every element has a position on the timeline as well as on the canvas, and the composition unfolds across both dimensions.

Every editing operation in a video composition runs client-side. Trimming, splitting, arranging, audio mixing, captioning, none of it requires a server. The browser does the work.

A video composition is built from elements that can be arranged across time as well as across space.

• Multi-track editing. Video clips, image overlays, text overlays, stickers, and audio tracks running simultaneously on separate tracks.
• Trim, split, join, and arrange. Modify clips, reorder segments, stitch content together on the timeline.
• Animations. Entrance, exit, and looping animations applied to design elements, time-anchored to the timeline.
• Captions. Time-synced text overlays, added inside the composition as designed text blocks (not external subtitle files).
• Audio. Music, voiceover, and sound effects as independent tracks alongside video content, each with its own volume.
• Chroma key. Green-screen background removal applied per video clip.
• Templates with placeholders and variables. The same template machinery that powers static design templates: a Creator builds a video template, an Adopter fills in placeholder clips and variable text.
• Headless and programmatic. The full composition API is available server-side, so video can be assembled and exported at scale without a user or UI.

Each of the patterns below maps to a real production category for video composition.

Social media video for brands and creators. Footage combined with branded lower thirds, logo animations, background music, and calls to action, exported as MP4 ready for upload. Templates make it possible to produce consistent output across a campaign series without rebuilding from scratch each time.

Personalized video at scale. E-commerce and SaaS teams produce videos where variable elements (recipient name, product image, offer text) swap per viewer while the surrounding structure (background, music, motion graphics) stays constant. Role-based templates with placeholders and variables drive this workflow.

Product showcase videos. Retailers generate product videos automatically from catalog assets. A template defines the structure; the engine populates each variation from product data. No manual editing per SKU.

Short-form content and Reels. The built-in timeline editor gives users a familiar editing experience directly inside the product. Stories, reels, and TikTok-style content with branded intros, captions, and transitions.

Training and instructional content. Screen recordings, presenter footage, and chapter titles assembled into branded instructional videos. Everything runs client-side, no server required.

Video composition requires the scene to be initialized in video mode. A design scene has no timeline and produces image or PDF output; a video scene has a timeline and produces video output. The mode is set at scene creation and cannot be changed afterward.

Video mode relies on modern web codecs (WebCodecs API), available in Chromium-based browsers (Chrome, Edge, Brave) and the most recent versions of Firefox and Safari. Video mode on mobile web has limitations due to browser codec support; CE.SDK’s native mobile SDKs are the recommended path for video on iOS and Android.

See timeline for the editing surface that drives composition, video-editor for the Starter Kit that surfaces it, and caption for the caption-specific block model.