build¶

Assemble a reel from a storyboard: render each card to a frame, crossfade them into a 1080×1920 H.264 video, and (unless --silent) mix the narration over the music bed. Rendering shells out to ffmpeg behind the Renderer interface.

Usage¶

# Workspace build (the authoring loop): --workspace is a slug under the reel root
keryx reel build --workspace my-post

# Render without audio (cards use their storyboard `dur`)
keryx reel build --workspace my-post --silent

# Standalone build from a loose storyboard file
keryx reel build --storyboard board.json --out promo.mp4

Flags¶

Flag	Description
`--workspace`	Reel workspace slug under the reel root (`reels/<slug>`), the same slug used by `reel new` and `storyboard draft`. The storyboard, VO takes, music bed, and cover are read from that workspace.
`--storyboard`	A standalone `storyboard.json` path, used as-is. Overrides the workspace board when both are given.
`--theme`	Reel theme keyword (palette, fonts, music gain). Defaults to the configured `reel` default.
`--out`	Output `.mp4` path. Defaults to `reels/<slug>/reel-<slug>.mp4` for a workspace build, or `reel.mp4` for a standalone build.
`--cover`	Cover image path. Defaults to `reels/<slug>/cover.png` if present.
`--silent`	Render video only — no narration, no music. Each card must carry a `dur`.

Timing¶

With VO (a workspace vo/*.mp3 exists, not --silent): each card's on-screen duration is derived from its narration clip length plus lead and tail; cards crossfade. The music bed is mixed in under the VO at the theme's gain with an end fade.
Silent / no VO: each card uses its storyboard dur. A card with no dur is an error in this mode.

See the Testing page for the BDD scenario that exercises a silent workspace render end to end.