Audible Plex Downloader

A pure Go Docker application that authenticates with Audible, downloads audiobooks, removes DRM via FFmpeg, fetches enriched metadata from Audnexus, and organizes files in Plex-compatible Author/Title/Title.m4b structure.

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                    Docker Container (~80MB)                      │
├─────────────────────────────────────────────────────────────────┤
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────────────┐  │
│  │  Go Binary   │  │   FFmpeg     │  │   Alpine Linux       │  │
│  │   (~15MB)    │  │   (~30MB)    │  │      (~5MB)          │  │
│  └──────────────┘  └──────────────┘  └──────────────────────┘  │
├─────────────────────────────────────────────────────────────────┤
│                         Volumes                                  │
│  /config (auth, db)  │  /audiobooks (Plex)  │  /downloads (temp)│
└─────────────────────────────────────────────────────────────────┘

Components

Component	Technology	Purpose
Auth & API	Pure Go (`go-audible` lib)	OAuth, device registration, Audible API
Web UI	HTMX + Go templates	Dashboard, library browser, settings
Audio Processing	FFmpeg (subprocess)	AAX decryption, format conversion
Metadata	Audnexus API	Enriched book/author/chapter data
Database	SQLite (default) / PostgreSQL	Library state, queue, settings
Scheduler	`robfig/cron`	Automated library sync

Features

Authentication: Browser-based OAuth flow with Audible/Amazon
Library Sync: Automatic detection of new purchases (scheduled or manual)
Download Queue: Concurrent downloads with progress tracking
DRM Removal: FFmpeg-based decryption (AAX activation bytes, AAXC voucher)
Output Formats: M4B (single file) or MP3 (chapter-split), configurable
Metadata: Audnexus-enriched tags embedded in audio files
Plex Structure: {Author}/{Title}/{Title}.m4b + {Title}.chapters.txt
Web Dashboard: Real-time progress via SSE, library browser, settings

Implementation Phases

Phase 1: Project Foundation (2 days)

Initialize Go module
```
go mod init github.com/nick/audplexus
```
Create Dockerfile
- Multi-stage build: golang:1.22-alpine → alpine:3.19
- Install FFmpeg, ca-certificates
- Expose port 8080

Set up docker-compose.yml

services:
  audible-plex:
    build: .
    ports:
      - "8080:8080"
    volumes:
      - ./config:/config
      - /path/to/audiobooks:/audiobooks
      - ./downloads:/downloads
    environment:
      - DATABASE_TYPE=sqlite  # or postgres

Database abstraction
- Interface supporting SQLite and PostgreSQL
- Tables: books, download_queue, sync_history, settings, devices
- Migrations via golang-migrate

Phase 2: Audible Library Integration (depends on go-audible)

Import go-audible library
- OAuth flow integration
- Credential storage (encrypted)
- API client for library/download operations
Library sync service
- Fetch full library with pagination
- Compare with local DB, identify new titles
- Queue new books for download

Phase 3: Audio Processing Pipeline (2 days)

Download manager
- Concurrent downloads (configurable, default 2)
- Progress tracking
- Resumable downloads
DRM removal pipeline
- FFmpeg wrapper for AAX: ffmpeg -activation_bytes <bytes> -i input.aax -c copy output.m4b
- FFmpeg wrapper for AAXC: ffmpeg -audible_key <key> -audible_iv <iv> -i input.aaxc -c copy output.m4b
- Integrity validation (duration check)
Format conversion
- M4B: Direct copy from decrypted (fastest)
- MP3: Chapter-split using FFmpeg + chapters metadata
Cover art processing
- Download high-res cover
- Embed in M4B
- Save standalone cover.jpg

Phase 4: Metadata & Audnexus (1 day)

Audnexus API client
- GET /books/{asin} - Book metadata
- GET /authors/{asin} - Author details
- GET /chapters/{asin} - Chapter info
- Fallback to Audible data if unavailable
Metadata processor
- Merge Audnexus + Audible (Audnexus preferred)
- Fields: title, author, narrator, series, position, description, genres
File tagger
- Embed via FFmpeg metadata options
- ID3/MP4 tags

Phase 5: Plex Organization (1 day)

File organizer
- Structure: {library_root}/{Author}/{Title}/{Title}.{ext}
- Sanitize filenames (remove <>:"/\|?*)
- Series handling: {Title} - {Series}, Book {N}

Chapter file generation

{Title}.chapters.txt format:

00:00:00.000 Opening Credits
00:01:23.456 Chapter 1
00:45:12.789 Chapter 2
...

Post-processing
- Clean temp files
- Update database
- Optional: Trigger Plex library scan via API

Phase 6: Web UI (2 days)

HTMX-based interface
- Dashboard: overview, recent downloads, sync status
- Library browser: searchable/sortable table
- Book detail: metadata, cover, actions
- Download queue: progress bars (SSE)
- Settings: auth, output format, paths, schedule
Authentication UI
- /auth/start - Redirect to Amazon OAuth
- /auth/callback - Receive authorization code
- /auth/status - Current auth state

Phase 7: Scheduling (1 day)

Cron scheduler
- Library sync: hourly/daily/weekly/disabled
- Manual trigger via UI
- Quiet hours configuration
Notifications (future)
- Webhook on download complete
- Discord/Slack integration

Project Structure

audplexus/
├── cmd/
│   └── server/
│       └── main.go                 # Entry point
├── internal/
│   ├── audnexus/
│   │   └── client.go               # Audnexus API client
│   ├── audio/
│   │   ├── ffmpeg.go               # FFmpeg wrapper
│   │   ├── decrypt.go              # DRM removal
│   │   ├── convert.go              # Format conversion
│   │   └── tag.go                  # Metadata embedding
│   ├── database/
│   │   ├── interface.go            # DB abstraction
│   │   ├── sqlite.go
│   │   ├── postgres.go
│   │   ├── models.go               # Data models
│   │   └── migrations/
│   │       └── 001_initial.sql
│   ├── library/
│   │   ├── sync.go                 # Library sync logic
│   │   └── download.go             # Download manager
│   ├── organizer/
│   │   └── plex.go                 # File organization
│   ├── scheduler/
│   │   └── cron.go                 # Scheduled jobs
│   └── web/
│       ├── server.go               # HTTP server
│       ├── handlers/
│       │   ├── auth.go
│       │   ├── library.go
│       │   ├── downloads.go
│       │   └── settings.go
│       ├── templates/
│       │   ├── base.html
│       │   ├── dashboard.html
│       │   ├── library.html
│       │   ├── auth.html
│       │   └── settings.html
│       └── static/
│           ├── htmx.min.js
│           └── style.css
├── Dockerfile
├── docker-compose.yml
├── go.mod
├── go.sum
├── config.example.yaml
├── PLAN.md
└── README.md

Dependencies

Package	Purpose
`github.com/mstrhakr/go-audible`	Audible auth & API
`github.com/gin-gonic/gin`	HTTP router
`github.com/mattn/go-sqlite3`	SQLite driver
`github.com/lib/pq`	PostgreSQL driver
`github.com/golang-migrate/migrate/v4`	Migrations
`github.com/robfig/cron/v3`	Scheduler
`github.com/rs/zerolog`	Logging

Configuration

# config.yaml
server:
  port: 8080
  
database:
  type: sqlite  # sqlite | postgres
  path: /config/audible.db  # for sqlite
  # dsn: postgres://user:pass@host/db  # for postgres

paths:
  audiobooks: /audiobooks
  downloads: /downloads
  config: /config

output:
  format: m4b  # m4b | mp3
  embed_cover: true
  chapter_file: true

sync:
  schedule: "0 */6 * * *"  # every 6 hours
  enabled: true

plex:
  url: http://plex:32400
  token: ""  # optional, for library scan trigger

External Dependencies

go-audible: Pure Go Audible authentication and API library (separate repo)
FFmpeg: Audio processing (bundled in Docker image)

Verification Checklist

Future Enhancements

Multi-region support (UK, DE, FR, etc.)
Wishlist sync and purchase notifications
Audiobookshelf compatibility mode
Podgrab-style podcast support (Audible podcasts)
Discord/Slack notifications
Bulk re-download with updated metadata

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Audible Plex Downloader

Architecture

Components

Features

Implementation Phases

Phase 1: Project Foundation (2 days)

Phase 2: Audible Library Integration (depends on go-audible)

Phase 3: Audio Processing Pipeline (2 days)

Phase 4: Metadata & Audnexus (1 day)

Phase 5: Plex Organization (1 day)

Phase 6: Web UI (2 days)

Phase 7: Scheduling (1 day)

Project Structure

Dependencies

Configuration

External Dependencies

Verification Checklist

Future Enhancements

FilesExpand file tree

PLAN.md

Latest commit

History

PLAN.md

File metadata and controls

Audible Plex Downloader

Architecture

Components

Features

Implementation Phases

Phase 1: Project Foundation (2 days)

Phase 2: Audible Library Integration (depends on go-audible)

Phase 3: Audio Processing Pipeline (2 days)

Phase 4: Metadata & Audnexus (1 day)

Phase 5: Plex Organization (1 day)

Phase 6: Web UI (2 days)

Phase 7: Scheduling (1 day)

Project Structure

Dependencies

Configuration

External Dependencies

Verification Checklist

Future Enhancements