ADR 0017: Video Transcript Capture: yt-dlp over Cobalt
Status
Accepted.
Context
Genesis captures video transcripts for knowledge graph ingestion and community documentation. yt-dlp and Cobalt were evaluated. yt-dlp is a mature YouTube downloader with transcript extraction. Cobalt is a privacy-first web app for ad-free media downloads.
Decisions
D1: yt-dlp is the primary transcript extraction tool.
yt-dlp is the standard for downloading YouTube video/audio and extracting transcripts. It is available via pip, cargo, and system package managers. It is actively maintained and proven in production. It is self-hosted with no API key or external service dependency. It integrates via Python, Node, or shell subprocess. Maintenance cost is periodic updates to keep pace with YouTube API changes.
D2: Cobalt is not used as a transcript extraction tool.
Cobalt is a web app designed for public benefit with a strict zero-log policy. However, it is API-only with no self-hosted binary. Its API focuses on media download and remuxing. It is not designed for subtitle extraction. Routing Genesis requests through a third-party web service creates a dependency with rate limiting risk. For an autonomous agent at scale, this violates community data sovereignty principles.
Positive
yt-dlp is self-contained with no API keys or external dependencies. Transcript extraction integrates into existing pipelines. yt-dlp handles captions, subtitles, and automatic translations. Maintenance is via periodic pip install -U yt-dlp in cron or CI.
Negative
yt-dlp requires regular updates to keep pace with YouTube. Automate via dependabot or CI. YouTube may rate-limit yt-dlp. kreuzcrawl with headless Chrome is a fallback.