Media Transcription

Durable, event-driven transcription of raw meeting media on the NAS. Inngest orchestrates; MLX Whisper (chunked ASR) and pyannote (whole-file diarization) run as detached local actor processes — no Inngest step ever holds a request open across inference. Built 2026-07-11 after the v1 monolith died to request-bound 2h timeouts and Whisper hallucination loops (design receipt: .brain/projects/transcription-pipeline-v2-2026-07-11.svx).

Where it runs (hard constraints)

• Flagg host worker only (hostFunctionDefinitions, launchd com.joel.system-bus-worker). Needs the direct NFS mount /Volumes/badass-media and the rig checkout.
• Local inference implementation: ~/Code/joelhooks/transcript-rig (public repo joelhooks/transcript-rig; override path with TRANSCRIPT_RIG_ROOT). Raw media on the NAS is immutable — the pipeline only writes derived artifacts.
• From any other fleet machine: send the event (Inngest routes it to flagg's worker) or SSH to flagg to inspect on-disk state.

Start a transcription

joelclaw send media/transcription.requested -d '{
  "requestId": "req-'$(uuidgen | tr 'A-Z' 'a-z')'",
  "sourcePath": "/Volumes/badass-media/joel/meetings/<meeting-dir>"
}'

• requestId is the idempotency key — always mint a fresh one; a reused id is silently deduped. Optional flags: "publish": false, "index": false (both default true).
• sourcePath must be under /Volumes/badass-media/ or the run fails NonRetriable.

Monitor

• joelclaw event <event-id> → run id; joelclaw run <run-id> for step trace. Orchestrator steps keep NN- prefixes for the pi job-monitor widget (packages/pi-extensions/inngest-monitor).
• Progress events: media/transcription.chunk.completed (per chunk, with index/total/cached), terminal media/transcription.completed or .failed.
• On-disk truth (flagg): <rig>/.transcript-rig-work/<artifactId>/
  • orchestration/plan.v1.json — chunk plan (requestId, tracks, chunk ids)
  • orchestration/actors/<chunkId>/status.v1.json — actor heartbeat/state
  • orchestration/actors/<chunkId>/actor.log — inference stdout/stderr
  • state.v1.json — rig stage (staged → transcribed → … → complete)
  • editorial/transcript.{md,txt,srt,vtt,tsv} — final outputs
• Published result: <sourcePath>/derived/transcripts/current.v1.json pointer + artifact directory.

Cancel

joelclaw send media/transcription.cancelled -d '{"requestId": "<the-request-id>"}'

Cancels all runs (cancelOn) AND triggers transcription-cleanup-v1, which SIGTERM→10s→SIGKILLs live actor process groups (identity-verified via ps — PID reuse safe) and writes orchestration/cancelled.v1.json, which blocks new actor spawns. Optionally include artifactId to skip the plan scan.

Resume / re-drive

Re-send media/transcription.requested with a fresh requestId and the same sourcePath. Everything valid on disk is adopted, nothing recomputes:

• Whole-track raw/asr/<sourceId>/asr.json passing the repetition screen ⇒ track done. A repetitive one is quarantined (.rejected-<ts>) and the track re-chunks.
• Existing chunk WAV layouts (raw/chunked/<sourceId>/chunks/NNN.wav) are adopted; offsets recomputed from ffprobe. Valid chunk out/<i>/asr.json ⇒ cached, no actor spawned.
• Diarization raw/diarization/<sourceId>.jsonl (first line parses) ⇒ cached.
• Remove orchestration/cancelled.v1.json first if the artifact was previously cancelled.

Failure modes (typed, in actor status / run errors)

Error	Meaning	Action
repetitive_output: …	Whisper hallucination loop survived collapse (decode mostly padding)	Retries respawn actors; deterministic loops usually pass after collapse-then-screen. Inspect the chunk WAV — genuinely silent/broken audio fails honestly
inference_required: …	A fast rig stage (resume --no-inference) found a missing claim check	Inference didn't complete/adopt; check chunk statuses
cancelled_by_signal	Actor's child died to un-initiated SIGTERM/SIGKILL (group kill, operator, or Bun's in-process signal-dispatch race)	Expected during cancel/reap; standalone occurrences mean someone killed processes manually
actor stalled	Heartbeat stale >3m	Watchdog killed + retried automatically
chunk_result_missing	Aggregation found no valid chunk output	Chunk failed all retries; see its actor.log
mount_unavailable	NFS mount down	media/transcription.blocked emitted; remount and re-drive

Design invariants (don't regress these)

• ASR outputs are parsed with parseAsrJson (mlx_whisper emits bare NaN).
• Repetition screening is collapse-then-screen (screenWithCollapse): consecutive-duplicate segments collapse to one; >50% collapsed ⇒ failed decode. Aggregation persists the collapsed form.
• ASR actors run --condition-on-previous-text False --hallucination-silence-threshold 2; diarization uses MPS (TRANSCRIPT_RIG_DIARIZE_DEVICE=cpu to opt out).
• waitForEvent results are verified in code against the spawned actorId — the dev-mode Inngest server leaks foreign events past match expressions.
• Known dev-server gap: concurrency keys (transcription-gpu limit 1) are not enforced; expect parallel whispers until the Inngest server is upgraded.

Code: packages/system-bus/src/transcription/ + packages/system-bus/src/inngest/functions/{media-transcription-pipeline,transcription-asr-chunk,transcription-diarize,transcription-cleanup}.ts.