/render-editorial-motion-podcast

name: render-editorial-motion-podcast
description: Assemble an editorial-motion podcast-clip ad from a config — a real clipped podcast MP3 carries the narrative while N flat 2-tone editorial-illustration keyframes are animated NOT by generative i2v but by DETERMINISTIC ffmpeg ken-burns (zoompan) + hard cuts (no crossfades, which expose geometric drift), each beat snapped to its spoken line, the real audio muxed, Whisper-driven captions burned only mid-sentence, and closed on a PIL brand end card — never AI-rendered text. This is the FREE deterministic assembly stage (ffmpeg ken-burns + hard concat + audio mux + captions + end card); the real audio is clipped from source and the keyframes come from create-image-fal. Use for the editorial-motion-podcast format.
status: active

render-editorial-motion-podcast

Assemble an **editorial-motion podcast-clip** ad from a config: a real clipped podcast audio line carries the whole narrative and every visual beat is timed to the sentence it describes, in a bold flat 2-tone editorial-illustration look ("a New Yorker spot-illustration that moves"). The motion is **not generative video** but deterministic ffmpeg ken-burns on static keyframes, so it reads as a printed page that moves. This capability is that **FREE, deterministic assembly** — the ffmpeg motion, hard-concat, audio mux, caption burn, and PIL end card.

`scripts/config.example.json` is the worked example (Klarify "Rat Park", ~40.8s 1080×1920 9:16, 6 beats); `scripts/PIPELINE.md` maps every config block to its source step and `scripts/README.md` documents the free assembly.

Run

This is the **FREE, deterministic** assembly stage — it spends nothing on the motion layer. The paid inputs are separate: the real podcast MP3 is clipped from source (free ffmpeg) with its Whisper word timings, and one editorial-illustration keyframe per beat (chained ref images so cage/character geometry holds) comes from `create-image-fal` (Nano Banana). Given the clipped audio + `words.json` + the per-beat keyframes + the real brand wordmark PNG, `render-editorial-motion-podcast` renders each keyframe as a ken-burns segment, hard-concats on the beat, muxes the real audio, burns the mid-sentence captions, and composites the PIL end card → the master. Re-cuts reuse the existing audio / keyframes and cost **$0**.

Contract (the free assembly)

• **A spoken narration carries the whole spot — no generated SONG.** Mux the provided

narration MP3 (`-map 0:v:0 -map 1:a:0`) — a real clipped podcast line (preferred) OR an approved generated VO (`create-vo-elevenlabs`). Never a sung/generated track. (Clip-vs-generate is the recipe's STEP-0 intake decision — if no source episode is supplied, ASK the user.)

• **NO generative i2v — deterministic ffmpeg ken-burns only.** Animate each static keyframe

with `zoompan` (push-in / pull-back, 1.0→~1.06×, 24fps); Seedance/Kling are photoreal-trained and invent naturalistic middle states that collapse the 2-tone look. Never `-loop 1` with `zoompan d=N` (it balloons the duration); feed a single image and clamp with `-t` + `trim`.

• **Hard cuts on the beat — no crossfades.** Crossfades ghost two drifting cages through each

other; hard-concat each beat's segments and split long beats into micro-cuts (target 8–10 distinct visual moments). Each beat's visual STARTS within ~0.5s of its spoken line.

• **Captions from Whisper word-timestamps, ON only mid-sentence.** Burn `frosted-subtle`

captions while the speaker talks; leave silent/reflective beats and the end card uncaptioned. THREE mandatory rules (each bit us in prod — bake them in): 1. **NON-OVERLAP** — clamp every line to END before the next STARTS (`end = min(last_word_end + ~0.15, next_start - 0.03)`). Two boxes must never stack at the same spot; an end-tail bleeding into the next window is the #1 caption bug. 2. **SAFE AREA** — captions sit in the lower third, so the keyframe's subject must stay in the upper ~75% (see the recipe's `look_pack.caption_safe_area`). If a finished keyframe's subject intrudes into the caption band, deterministically **shift the subject UP** into the empty top space (PIL: paste up ~0.24H onto a canvas pre-filled with the exact paper color from a clean corner) — never let the box sit on the subject. 3. **BURN ENGINE** — prefer libass (`ass`/`subtitles` filter), but **check `ffmpeg -filters` first**: many builds (Homebrew) lack libass/drawtext. If absent, use the deterministic **overlay fallback** — render each line as a transparent PNG (frosted rounded box + white text, PIL) and composite via the ffmpeg `overlay` filter with timed `enable='between(t,st,en)'` windows. Same look, no libass.

• **End card via PIL from the real wordmark PNG — never AI-render brand text.** The lockup is

composited deterministically (stretched-gradient bg + feathered mascot crop + wordmark + tagline with a system font); a diffusion model garbles a wordmark ("therapits"). The video runs a ~1.5s silent hold past the audio on the end card (fade first/last 0.3s).

• **FFmpeg composite, deterministic, FREE.** Ken-burns each keyframe, hard-concat, mux the real

audio, burn the captions, hold on the end card → a 1080×1920 h264+aac master. No paid calls.