Recording → Transcription

Automatically transcribe any audio or video recording dropped into Nextcloud. The moment a file lands in MinIO, Decree generates a pre-signed URL, streams the audio directly to Whisper, and saves the transcript next to the original file — no manual steps, no intermediate storage.

How It Works

1. Phone uploads the recording

The Nextcloud mobile app auto-syncs your phone's recordings folder to Nextcloud. Any .mp3, .mp4, or .wav file uploaded this way flows into MinIO via Nextcloud's S3 external storage.

2. MinIO fires the webhook

When the file lands in MinIO, it POSTs an s3:ObjectCreated event to the Decree webhook endpoint. The rclone_src and rclone_prefix in the webhook config tell minio-router how to construct the rclone path used in all subsequent steps.

3. minio-router matches the file

minio-router scans every processor script in automations/lib/file-processors/ for a PATTERN= match against the full rclone path. The whisper-transcribe processor declares:

PATTERN='\.[Mm][Pp][34]$|\.[Ww][Aa][Vv]$'
IS_PRE_SIGNED=true

It matches .mp3, .mp4, and .wav case-insensitively. Because IS_PRE_SIGNED=true, the outbox message carries is_pre_signed: true — telling file-processor not to download the file.

4. file-processor generates a signed URL

Instead of downloading the file, file-processor calls rclone link to generate a pre-signed URL for the audio file and exports it as PRE_SIGNED_URL. No audio data touches the Decree container's disk.

5. whisper-transcribe streams to Whisper

whisper-transcribe.sh invokes whisper-transcribe.ts, which:

1. Calls streamS3File(PRE_SIGNED_URL) — does a HEAD for metadata, then fetches the audio as a blob
2. Wraps it in a File with the correct content-type
3. POSTs it to http://whisper:8000/v1/audio/transcriptions as multipart form data
4. Writes the returned transcription text to stdout

6. Transcript saved next to the original

The bash processor pipes the transcription text through rclone rcat directly into Nextcloud at the same path as the audio file, with .transcription.txt appended:

recordings/2026-04-22 Meeting.mp3
recordings/2026-04-22 Meeting.mp3.transcription.txt   ← created automatically

Prerequisites

• Nextcloud running with MinIO configured as S3 external storage
• MinIO webhook sending ObjectCreated events to the Decree webhook endpoint (see File Change → Process)
• Whisper container running and reachable at http://whisper:8000
• rclone configured with a nextcloud remote (or whichever remote matches your rclone_src webhook setting)
• Nextcloud mobile app with auto-upload enabled for your recordings folder

Setup

Step 1 — MinIO webhook

Follow the MinIO setup in File Change → Process to register the Decree webhook target and subscribe your recordings bucket to ObjectCreated events.

Step 2 — rclone remote

Ensure your rclone config has a remote that can access the files MinIO is receiving events for:

./existential.sh setup rclone

The remote name must match rclone_src in services/decree/webhook/config.yml (default: nextcloud).

Step 3 — Enable Whisper

Start the Whisper container if it isn't already running:

docker compose -f ai/whisper/docker-compose.yml up -d

Whisper will download the default model on first use. No further configuration is required — the whisper-transcribe processor defaults to letting Whisper pick its own model.

Step 4 — Confirm the processor is active

The whisper-transcribe processor is auto-discovered from automations/lib/file-processors/. No registration step is needed. Verify the pre-checks pass:

docker exec decree decree routine file-processor

Step 5 — Configure Nextcloud mobile auto-upload

In the Nextcloud mobile app, enable auto-upload for your phone's voice recordings or screen recordings folder. Files are uploaded to Nextcloud, synced to MinIO, and the transcription flow triggers automatically.

Customization

Override any of these in the processor script or pass them as frontmatter params:

Variable	Default	Description
FILE_SUFFIX	.transcription.txt	Suffix appended to the audio file path for the output
OUTPUT_RCLONE	nextcloud	rclone remote where the transcript is saved
WHISPER_MODEL	(empty — Whisper default)	Model name passed to the transcription API

Testing

Send a synthetic MinIO event to trigger the flow end-to-end:

curl -X POST http://localhost:48880/minio \
  -H "Authorization: Bearer <DECREE_MINIO_WEBHOOK_AUTH_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{"EventName":"s3:ObjectCreated:Put","Key":"recordings/test.mp3","Records":[]}'

Watch processing in real time:

docker logs -f decree

Inspect the completed run:

docker exec decree decree status
docker exec decree decree log <id-prefix>