beamrecorder/beam/beam-export

Beam export

Choose the delivery dimensions, duration, format and transparency from the user's brief. If those materially affect an unresolved new design, use ../beam-design/SKILL.md. Do not add an approval round when the export is already requested.

Live editor

Read tools describe render.frame and tools describe render.export. Use the actual open project ID:

{"projectId":"PROJECT_UUID","timeMs":2000,"output":"./review.png"}

beam-cli tools call render.frame @frame.json

render.frame captures a video timeline frame as PNG. For an image project, export PNG/WebP directly. Example video export arguments:

{"projectId":"PROJECT_UUID","output":"./demo.mp4","format":"mp4","preset":"high"}

beam-cli tools call render.export @export.json

For Screenshot, choose .png or .webp via the output path and omit format; that field accepts only mp4/webm. Respect existing files unless replacement is intended; overwrite: true is explicit.

Standalone renderer

beam-cli browser install
beam-cli motion job.json demo.mp4
beam-cli export request.json demo.webm
beam-cli frame request.json 2000 review.png
beam-cli export image.json composition.png

Install the browser only when missing, not on every render. BEAM_CHROMIUM_EXECUTABLE may select an existing compatible browser. Standalone motion job structure lives in ../beam-composition/references/publish.md.

A video render needs a complete export snapshot and resolvable assets. A saved desktop project alone may not contain that full render request. Prefer live render.export for an open desktop project instead of guessing missing session state. Resolve project-media:/blob: resources before standalone export.

The default backend is WebCodecs, independent of desktop preferences. --backend ffmpeg-vaapi is experimental Linux GPU export requiring a compatible X11/XWayland display, drivers, native artifacts and external matching FFmpeg libraries. It is not a portable speed switch. Default headless software rendering does not require a desktop display.

Review and deliver

Inspect the actual exported files, not only a browser preview:

• First visible frame, representative holds, transition midpoints and last valid frame.
• Text fit at delivery size, crisp UI, aspect/crop, expected layers, alpha/edges and no missing resources.
• For video, real duration, dimensions, frame rate and audio playback/stream presence.
• For animation, repeated/reverse seeks at the same time produce the same state.

Use an available image viewer and video/metadata tools. If they are unavailable, report the exact verification limit. Do not say a video is visually verified because a file exists or a renderer returned success.

Return the output path and retain the editable document/HTML source. Report failures honestly; never replace a failed render with a placeholder and describe it as finished. Uploading or publishing is a separate action requiring authorization from the user's task.