Knips

Native macOS screen recorder in FreePascal — Knips, from the German knipsen, to snap a picture: the shutter sound, borrowed for a tool that catches what is on your screen. Pick a display, a region, or a window; get an .mp4 or .mov back, an animated GIF, or a truecolour APNG — or trim the movie itself without re-encoding a frame. Capture is ScreenCaptureKit, the file is written by AVAssetWriter with hardware H.264, the GIF and APNG encoders are pure Pascal, and the whole thing is one dependency-light binary built with lwpt. It grows out of the lantaarn capture core toward what Kap was: see VISION.md.

Install

lwpt install && lwpt build    # produces build/knips

Usage

./build/knips app                                     # menu bar: drag a region, click to stop
./build/knips probe                                   # verify the toolchain path once
./build/knips displays                                # what can be recorded
./build/knips record --out=demo.mp4                   # main display, 30 fps, Ctrl-C to stop
./build/knips record --out=demo.mp4 --rect=100,80,1280,720 --fps=60
./build/knips record --out=app.mov --window=<id>      # id from `knips windows`
./build/knips record --out=demo-raw.mp4 --smooth-cursor  # no pointer in the movie
./build/knips render --in=demo-raw.mp4                # -> demo.mp4, the deliverable
./build/knips render --in=demo-raw.mp4 --effects=zoom,big-cursor
./build/knips export --in=demo.mp4 --out=demo.gif     # animated GIF, 20 fps
./build/knips export --in=demo.mp4 --out=demo.gif --cursor=smooth
./build/knips export --in=demo.mp4 --out=demo.gif --width=800 --trim=1.5,4
./build/knips export --in=demo.mp4 --out=demo.apng    # truecolour APNG, no palette
./build/knips export --in=demo.mp4 --out=cut.mp4 --trim=1.5,3.5   # passthrough trim
./build/knips mcp                                     # MCP server on stdin/stdout

The menu-bar app records a take raw and renders the deliverable from it on every stop, so the effects are a decision you can change afterwards. On the command line the two halves are yours to sequence — record writes exactly the file you name and render writes the deliverable beside it, which is why the example above names its take demo-raw.mp4 — and over MCP record_stop writes one movie and the separate render tool writes the second pair. In every case: knips render draws the pointer back and applies Zoom on Click from the take's event sidecar, and --effects picks which — zoom, as-recorded, smooth-cursor, big-cursor, no-cursor, none. knips export takes the same list, plus --cursor=as-recorded|none|smooth|big for a GIF or an APNG.

knips mcp serves the same capabilities to an AI client over the Model Context Protocol — list_displays, list_windows, take_info, record_start / record_stop / record_status, render, export_gif, export_apng, export_trim — using pascal-mcp-sdk. Recording is non-blocking: the server keeps answering while it captures. Raw takes are there too: record_start takes smooth_cursor and render applies the effects afterwards, so an agent's recording can still change its mind. The pointer track is only as dense as the client's record_status polling, and the server says so (docs/quick-start.md).

tools/make-app.sh wraps the built binary in a menu-bar-only build/Knips.app (docs/deployment.md).

macOS prompts once for Screen Recording. Flags, exit codes, and the verification loop are in docs/quick-start.md.

Background

The default build carries no linker flags. ScreenCaptureKit needs an Objective-C object to deliver frames to, and an FPC-declared objcclass makes the current Apple linker demand -ld_classic; Knips builds that object through the Objective-C runtime API instead (ADR-0002). Encoding and muxing are AVAssetWriter's job (ADR-0001); the capture bindings are vendored from lantaarn (ADR-0003, porting notes).

Contribution

lwpt install && lwpt build && lwpt test — see docs/quick-start.md and AGENTS.md.

References

• Agent instructions
• MIT License