The failing "poison" jobs were 800MB+ 4K VR videos: the agent pulled the ENTIRE
file into memory (r.content) just to sample a few frames, which buffered ~1GB in
RAM and — on any slow/contended media store — got cut off mid-download
(ChunkedEncodingError), failed, and re-leased forever. Measured the media read at
~4–6 MB/s (raw off the share, curator out of the path), so no serving-layer tweak
helps; the file simply shouldn't be fully downloaded.
Environment-agnostic fix (works for any deployment, completes even when slow):
- media.sample_frames_from_url(): point ffmpeg straight at curator's /images URL.
It Range-reads only the video index + up to max_frames of content — never the
whole file — and reconnect flags resume a dropped transfer instead of failing.
Generous, env-tunable timeout (FFMPEG_TIMEOUT, default 1200s) = completion over
speed. Removes the bytes-based sample_frames (dead once videos stream).
- worker._download_decode: videos now stream (no fetch_image, no RAM blowup);
stills still download+decode. On an ffmpeg miss, probe curator liveness
(client.is_reachable) → fail the job if curator is up (unprocessable file, stops
the infinite re-lease) vs release if curator is down (transient, survives a
redeploy). Auth header passed so it works whether or not /images is gated.
Build marker 2026-07-01.6. Refs issue #1225.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ttrj5P7upUTueSfoJcxEqa
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