Check requirements
Masterselects requires Chrome 113+ with WebGPU support. A dedicated GPU is recommended for full performance at high resolutions. Integrated GPUs work but may limit frame rates when compositing multiple layers.Open
chrome://gpu and confirm that WebGPU shows as enabled. If it is disabled or blocked, check your Chrome flags and GPU driver.Open the app
Navigate to the Masterselects app URL in Chrome. No installation or account is required.To run it locally from source:Then open
http://localhost:5173 in Chrome.Import media
Drag and drop files directly onto the Media Panel, or click Import to open a file browser.Masterselects supports the following formats:
¹ H.265 decode depends on OS and hardware — full support on Windows, partial on macOS/Linux.
| Category | Supported formats |
|---|---|
| Video containers | MP4, MOV, WebM, MKV, AVI, M4V |
| Video codecs | H.264 (AVC), H.265 (HEVC)¹, VP8, VP9, AV1 |
| Audio codecs | AAC, MP3, Opus, Vorbis, FLAC, WAV/PCM |
| Images | PNG, JPG, WebP, GIF, BMP, AVIF, SVG |
| 3D models | OBJ, glTF, GLB, FBX (rendered via Three.js with lighting) |
MOV files work because they share the same ISO BMFF container as MP4. MKV works if it contains a browser-decodable codec such as H.264 or VP9. Files with unsupported codecs (e.g. ProRes in MOV) fall back to the Native Helper decode path when available.
Add clips to the timeline
Drag clips from the Media Panel onto a timeline track. Clips snap to the playhead and to each other by default.Basic editing shortcuts:
| Key | Action |
|---|---|
Space | Play / pause |
C | Cut clip at playhead |
J / K / L | Reverse / pause / forward (shuttle) |
Ctrl+C / Ctrl+V | Copy / paste clips |
Ctrl+Z / Ctrl+Y | Undo / redo |
I / O | Set in / out points |
Ctrl+S | Save project |
Add effects
Click a clip in the timeline to select it, then open the Properties Panel on the right.From the Properties Panel you can:
- Add one or more of the 30 GPU effects (color correction, blur, keying, distort, stylize)
- Choose from 37 blend modes
- Animate any property with keyframes — right-click a property and select Add Keyframe
- Apply vector masks with the pen tool
Export
Open the Export Panel from the top menu or panel tabs.Choose an export mode:
Select your output container (MP4 or WebM), codec, and resolution, then click Export. The file downloads automatically when encoding is complete.
| Mode | Best for |
|---|---|
| WebCodecs Fast (recommended) | Zero-copy GPU export — the GPU renders, WebCodecs encodes directly |
| HTMLVideo Precise | Frame-accurate export when WebCodecs Fast produces sync issues |
| FFmpeg WASM (experimental) | ProRes, DNxHR, FFV1, and other professional codecs |
| FCPXML | Round-trip interchange with Final Cut Pro or DaVinci Resolve |