Validated end-to-end on a real remux file (h264+ac3 mkv). The riskiest part of the
Plex epic — on-the-fly playback from the local file — now proven.
- app/plex/stream.py: seek-restart HLS session model (one ffmpeg per item, restarted
at a seek offset via -ss). Video stream-COPY (I/O-bound, CPU-light — fine on the
GPU-less prod host) + audio→aac only when not already aac. Maps first video+audio,
drops subtitles (no VTT rendition clutter). Session cap + idle reaper.
- routes: POST /stream/{rk}/session?start= (direct→raw url, remux→HLS session,
transcode→501 P3), GET /stream/{rk}/file (206 range, direct), /index.m3u8, /seg_n.ts.
- KEY FINDINGS (hard-won): (1) ffmpeg -hls_playlist_type VOD does NOT write the
playlist mid-run (only at finalize) → use EVENT (append-only, appears immediately),
which suits the seek-restart model; (2) naive per-segment copy + keyframe-indexed
extraction are both unreliable (non-uniform/imprecise segments) — ffmpeg's own HLS
muxer is the only correct segmenter; (3) dev slowness was the Windows /downloads
bind-mount write + SMB read → PLEX_HLS_DIR env points scratch at fast container-local
/var/tmp on dev (prod keeps download_root, fast local disk).
4e9b18cda9