beamrecorder/beam/beam-video-editor

Beam video editor

Read ../beam-cli/references/authoring.md before a live edit. For a new piece without visual direction, use ../beam-design/SKILL.md; for motion or HTML, add ../beam-animation/SKILL.md and ../beam-composition/SKILL.md only when needed.

Inspect before changing

Read the actual video snapshot: assets, clips, tracks, source/timeline intervals, enabled states, locks, scenes, animation tracks, zooms and render settings. Determine which recording contains the requested action. Do not replace an existing edit with a newly fabricated document.

Standalone inspect accepts saved project/composition/export-request JSON. edit INPUT COMMANDS.json OUTPUT applies a command array to a separate output; it does not modify an already open editor. A project JSON alone may not contain all render settings and resolved session media needed for export.

Timeline changes

Use beam-cli commands and beam-cli docs commands. Common payloads:

[
  {"type":"clip.move","payload":{"clipId":"CLIP_ID","startMs":0}},
  {"type":"clip.trim","payload":{"clipId":"CLIP_ID","edge":"end","timeMs":4000}},
  {"type":"clip.rate","payload":{"clipId":"CLIP_ID","rate":1.25}}
]

These values demonstrate command shape; derive real timings from the source and snapshot. Times are milliseconds. Split, trim and playback-rate changes affect source mapping; inspect the resulting intervals rather than subtracting seconds blindly. Do not speed up narration until it becomes unintelligible.

clip.add requires a complete valid clip; there is no generic clip.insert command supplying defaults. asset.add likewise needs complete metadata. assets.import copies media into the project but does not create a timeline clip. Use ../beam-assets/SKILL.md for media/font handling.

Use native text clips for editable titles and labels. Preserve existing text style and imported font metadata. Scene groups and animation tracks use the engine schema; read it before creating a new graph.

Presentation, zooms and lenses

Live render.patch supports canvas, background, blurPercent, zooms, zoomMotionBlur and zoomAutoFollow. Read the current value and change the supported field, retaining everything outside the requested scope. Recorded cursor data, font resources, cursor packs and render metadata are host-owned, not arbitrary patch targets.

Use 2D focus, 3D perspective or glass lenses to explain a real action. Keep UI text readable and the focus inside useful source bounds. Read actual zoom/loupe records from the snapshot and installed docs; do not invent a CLI zoom.add command because the editor has an Add action. Regeneration can replace auto-generated zoom/loupe placement; preserve manual work and locks.

Captions use real timed words/segments and native document commands. Beam's current local Whisper transcription UI exports JSON; do not promise SRT/VTT output or invent a transcription CLI tool. The CLI tool catalog is the authority for what an agent can invoke directly.

For audio, use ../beam-audio/SKILL.md. HTML media is muted in live HTML preview; place audible media on the Beam timeline when building a composition.

Review

Remove waiting time while keeping the action understandable. Check continuity around every trim/cut, text readability, cursor emphasis, audio alignment and final duration. Render representative frames and an actual video using ../beam-export/SKILL.md; a valid transaction alone does not prove the edit looks right.