The problem
A timelapse starts as a folder. A camera on a tripod takes one photo every few seconds through a sunset, a storm or a building site, and the evening ends with hundreds or thousands of files.
Turning them into a video usually means a video editor built for clips, or a slideshow maker that does not know what a frame rate is. The photographer wants to see the day turn to night, in the right order, at the right speed and in the right shape for where it will be posted.
The product
10Lapse is a native Windows 11 app. A folder, a few chosen photos or a drag onto the window starts a project. It reads JPEG, PNG and TIFF, and HEIC and camera RAW with the Microsoft Store’s extensions, and puts the photos in the order they were taken.
The speed is set in frames per second, by the video’s length or in seconds per photo. The frame matches the photos or is set to 16:9, 9:16, 1:1, 4:5 or 4:3. A live preview and a filmstrip show the sequence, with markers where photos seem to be missing. Removing a photo takes it out of the video, never off the disk.
Export writes an MP4 in H.264, or in HEVC where the PC can encode it, from 720p to 4K, on the graphics card’s video encoder where there is one. It keeps going when the window is minimised and keeps the PC awake until it is done.
Version 3.1 adds what a timelapse needs after the shoot: deflicker, which reads each photo’s exposure settings and turns a sunset’s steps into a smooth ramp; frame blending of 2 to 16 photos, for light trails; crop and pan with up to 4× zoom; an animated GIF; music under an MP4; holds of up to 10 s at either end, up to five plays or a boomerang; and .10lapse project files.
The app works offline, in six languages, and every failure says what happened and what to do next.
How it’s made
Version 3.0 is a rewrite from scratch: C# on .NET 10, WinUI 3 and the Windows App SDK 2.5. Win2D draws the frames, Media Foundation’s sink writer encodes them, CsWin32 generates the calls into Windows and CommunityToolkit.Mvvm the view models. xUnit v3 runs the tests, and Axe.Windows checks the running window against the Accessibility Insights rules.
It shipped as an update to the existing Store listing, with the same package identity, and went live on 21 Oct 2026 at full rollout. Windows 10 is not supported.
The repository’s first commits are the UWP app of 2017, and the old code is kept at a tag. The rewrite began on 18 Oct 2026 and was built with Claude Code agents through numbered GitHub issues in waves, with docs/STATUS.md as the shared state they read first. An implementer agent builds each issue in its own git worktree, at most two at once. A read-only reviewer agent reads the pull request, and a fresh agent fixes what it finds. Three of 3.1’s features (crop and pan, music and frame blending) were built by the orchestrating session itself, at Sven’s request, without a review agent.
There is no CI. Before every merge a local gate builds the app with warnings as errors, runs every test and builds Release.
Details
The design direction is called The Quiet Film Gate: native Fluent chrome (Mica, stock WinUI controls, Segoe UI Variable), one golden-hour amber, #E8962E, for the primary action, and the photos as the only strong colour. Motion plays where something is made. On import the first photo develops like a print while thumbnails file into the strip, frames pass an amber gate during export, and the finished video plays in place. With Windows animations off, each movement becomes a short fade.
The 59-second film was made in code for this site. A mountain lake is drawn from 17:42 to night, the window is rebuilt from the design tokens with the app’s own strings, and the score is synthesised in code on the picture’s 120 BPM timeline. There are no real photos in it. Every title stays whole and still for at least 0.4 s plus one second per 15 characters, and every second of the film passes the WCAG flash thresholds, checked with the method Popote’s film uses.
Status as of 26 Oct 2026: version 3.1, the one in the film, has been on the Microsoft Store since 25 Oct. Version 3.0, the rewrite, replaced the old app there on 21 Oct.
