Root cause of the failing downloads: containers usually have no working IPv6 route, but
googlevideo CDN hosts advertise AAAA records, so the downloader tried IPv6 and failed with
'[Errno -5] No address associated with hostname'. Small clips happened to use IPv4; long videos
(more CDN requests / the ffmpeg path) hit IPv6 and died.
- yt-dlp source_address=0.0.0.0 forces IPv4 for every connection (== --force-ipv4). Verified: the
full video+audio download completes cleanly.
- Also: retry (resume) now resets the shared asset from 'error' to 'pending', so it actually
re-downloads — previously the requeued job instantly re-inherited the asset's stale error
because the worker short-circuits a job whose asset already errored.
- Dropped the localdev DNS override (wrong hypothesis; the issue was IPv6, not the resolver).
- Kept yt-dlp retries/fragment_retries/socket_timeout for transient blips.
Verified end-to-end in the worker: two previously-failing long videos now download to done.
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