Render Cosmic Mythology Voiceover Agent Skill

render-cosmic-mythology-voiceover

Assemble a cosmic-mythology-voiceover reel from a config: a faceless, cinematic storytelling

video where a warm, contemplative spoken voiceover carries the whole narrative (a "myth as

teacher" reframe) over a slow, weighted Ken-Burns zoom across curated cosmic / mythology stills

in ONE ethereal deep-indigo + gold look, with ONE on-screen hook line and burned captions. This

capability is the FREE, deterministic assembly — the weighted beat-sync sequencing, the

Ken-Burns render, the concat, the VO composite, the hook overlay, and the caption burn.

scripts/config.example.json is the worked example (WishAstro "Saturn isn't your villain", ~31s

1080×1920 9:16, 12 weighted Ken-Burns cuts); scripts/PIPELINE.md maps every config block to its

source step and scripts/README.md documents the free assembly.

Run

There is a single runnable script — scripts/render.py (config-driven, ffmpeg + Pillow only, NO

API keys and NO drawtext/libass required):

python3 scripts/render.py --config config.json --vo working/vo2/vo_atempo.mp3 \
  --stills-dir working/stills --out working/final.mp4 \
  [--words working/vo2/words.json] [--endcard working/endcard.png]

This is the FREE, deterministic assembly stage — it spends nothing. The paid inputs are

separate capabilities — the spoken VO (create-vo-elevenlabs, ElevenLabs eleven_v3 from a

tone-tagged script, atempo time-stretched so the delivered duration sets the timeline) and the 4–6

hero stills in one look pack (create-image-fal, Flux Pro 1.1, reused as repeats to reach the

~10–12 cuts). Given the VO + the stills + the per-cut weight array + the hook line, render.py

distributes the cuts across the VO duration by the weighted formula, Ken-Burns-renders each still,

concats, composites the VO, fades the hook line on over the open, burns the captions, and (if

--endcard is passed) appends a brand end card → the master + a poster. Re-cuts reuse the existing

VO / stills and cost $0. See scripts/README.md §0 for the full arg contract.

Contract (the free assembly)

• The spoken VO carries the narrative — no talking head, no sung song. The generated/supplied

VO IS the audio bed (no music bed by default); do not add a presenter or a second bed.

• Plan the timeline AROUND the delivered VO duration. The VO is atempo time-stretched (clamp

the factor ≤ ~1.25 so the voice never chipmunks); its delivered length sets the timeline — never

trim the VO to a pre-planned grid.

• Weighted beat-sync, not a fixed grid. For each cut, cut_dur = VO_dur × weight / Σweights —

heavier weights hold longer on the emotional beats (the open, the reframe, the close); the setup

cuts run shorter. Every cut stays proportional to the whole VO.

• Ken-Burns per still. Render each still with scale 2×, center crop, and a zoompan to the

configured zoom_end (~1.10); apply zoom_out on the flagged cuts; fade_in on the FIRST cut

and fade_out on the LAST. Stills are reusable — the sequence repeats a few across the cuts.

• ONE cosmic look, no in-world text. Every still reads in the single deep-indigo + gold +

volumetric-light look; the reel's only text is the hook + the captions, added in post (the "no

text, no words" descriptor keeps words off the stills).

• ONE hook line, alpha-faded on over the open. Burn the single reframe line over the OPEN only

(fade in ~0.5s, hold, fade out ~0.6s) — never a persistent caption, never in-world. render.py

does this with a PIL PNG + ffmpeg fade=…:alpha=1 (no drawtext dependency, since stock ffmpeg

often lacks it); an ffmpeg drawtext alpha window is an equivalent alternative where available.

• Captions from Whisper — bottom, white. VEED/Whisper subtitle burn tracks the spoken VO in the

bottom third, white #FFFFFF. If the host ffmpeg lacks libass (no subtitles/ass filter),

render the cues as timed PIL PNG overlays (ffmpeg overlay=…:enable='between(t,st,en)') at the

same bottom placement — a free local Whisper + ffmpeg burn is the fallback to the VEED tier.

• FFmpeg composite, deterministic, FREE. ffmpeg-concat the Ken-Burns clips, composite the VO

under the picture (libx264 crf 18 + aac 192k), burn the hook alpha-fade + the caption track →

a 1080×1920 h264+aac master (~31s). No paid calls, no keys (the local caption fallback is free).