Render Editorial Motion Podcast

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):

• 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.

• 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.

• 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.