Podcast Video Publisher

Podcast Video Publisher

Turn a folder of podcast audio + a folder of artwork into a complete, correctly-ordered YouTube Podcasts section. Battle-tested by shipping a 12-episode season in one day (Ghost Signals with Kannaka — canonical home: https://github.com/NickFlach/kannaka-radio).

What This Skill Does

1. Render — scripts/podcast-slideshow.py builds a 1920×1080 MP4 per episode: art slides (~45 s each, blur-filled background, sharp center panel, dip-to-black fades) plus a generated cover card (hero art + episode title) that doubles as the thumbnail. Video is padded then muxed -shortest, so A/V drift is 0.00 s by construction.
2. Publish — scripts/podcast-upload-batch.js runs resumable phases: upload → thumbs → playlist → order → retire → verify, with all progress in a state file so any failure (quota, rate limit, network) resumes exactly where it stopped.
3. Self-heal — scripts/podcast-finisher.js is a long-running watcher that retries rate-limited thumbnails (2 h cadence) and applies playlist positions the moment position updates become possible.

All six scripts in scripts/ are self-contained (Node stdlib + ffmpeg + Pillow only — no npm install).

Setup

1. Drop the scripts/ folder into your project root (/scripts/). The scripts treat the parent of scripts/ as the project root.
2. Install prerequisites: ffmpeg + ffprobe on PATH, Python 3 with Pillow, Node 18+.
3. Create YouTube OAuth credentials: node scripts/youtube-grant.js (prompts for an OAuth client id/secret from Google Cloud Console with the full youtube scope). Writes /.youtube.json — never commit this file.
4. Set PODCAST_PLAYLIST in scripts/podcast-upload-batch.js and scripts/podcast-finisher.js to your podcast playlist ID.
5. Fonts: cover cards default to Segoe UI (C:/Windows/Fonts/) — edit FONT_BOLD/FONT_REG in podcast-slideshow.py on Linux/macOS.

Project Layout

/
├── .youtube.json                     # OAuth creds (gitignore!)
├── scripts/                          # this skill's scripts
└── workspace/podcasts/
    ├── episodes.json                 # [{num, title, audio}, ...]
    ├── metadata.json                 # [{num, title, description, tags,
    │                                 #   video, cover, oldVideoId?}, ...]
    ├── art/                          # square images ≥1024px
    │   └── manifest.json             # [{file, title}, ...]
    ├── renders/                      # output MP4s + cover PNGs
    └── upload-state.json             # created by the pipeline (gitignore)

Quick Start

python scripts/podcast-slideshow.py --all      # render (idempotent)
node scripts/podcast-upload-batch.js           # publish, re-run to resume
node scripts/podcast-finisher.js               # only if thumbs/order pending

Phase Reference (podcast-upload-batch.js)

Run one phase with --phase . Delete an entry from upload-state.json to force a redo of just that item.

YouTube Gotchas (all hit in production — trust these)

1. Uploads can silently vanish. videos.insert may return 200 + a video ID and the video is simply gone minutes later — no error, no rejectionReason. Always re-verify IDs with videos.list before playlist adds (which otherwise fail "Video not found"), and keep uploads resumable per-item. Re-uploading the identical file works.
2. Thumbnails: 2 MB hard limit + long rate-limit. 1080p PNGs blow the 2,097,152-byte cap (413) — save covers as JPEG quality ~88. After ~10 rapid sets you get 429 "too many thumbnails recently" and the cooldown outlasts 40+ minutes — hence the finisher's 2 h retry cadence.
3. Podcast playlists force publish-date ordering. Display order is exactly publishedAt DESC; insert order is irrelevant, delete + re-insert changes nothing, and playlistItems.update with a position fails with "Playlist sort type need to be MANUAL to support position". publishedAt is immutable (a private→public round-trip does NOT reset it) and the sort setting is not in the Data API. Fix: flip the playlist to Manual ordering in YouTube Studio (one click, owner only), then run --phase order. Or upload in episode order in the first place.
4. Daily quota is not always 10k. A 13-upload day (~21k nominal units) cleared fine. Don't pre-abort on quota math, but assume any phase can die mid-run — that's what the state file is for.

Design Notes

• Cover cards are drawn with Pillow (hero art right, blurred/darkened art as backdrop, kicker + wrapped title + footer left) — consistent branding and readable at thumbnail size.
• Slides render as independent per-slide MP4 segments (parallel, resumable) joined with the concat demuxer; audio is muxed once at the end, so chapter timestamps in descriptions stay valid.
• Descriptions: keep every factual claim traceable to the episode audio (transcribe with faster-whisper if needed), and scrub anything private before publishing — no server names, IPs, file paths, or credentials.