Playback Notes Sync

Playback Notes Sync is an Android tablet app for capturing handwritten playback notes with an S Pen. It combines a running MM:SS timer, optional MIDI Time Code (MTC) synchronization, on-device handwriting recognition, and CSV export for post-production workflows.

The interface is in English; handwritten notes and project names remain entirely user-controlled.

Highlights

• Project-based note sessions stored locally on the device.
• MM:SS transport with Start, Pause, Resume, and direct time-code adjustment.
• Handwritten note cards designed for S Pen use, including stylus-button erasing.
• Department buttons on every note: MIX, DIAL, SFX, STP, FOL, ADR, and CONC.
• Notes are automatically sorted by time code. CLONE TC creates an adjacent empty note at the same time code.
• OCR through Google ML Kit Digital Ink Recognition. The French recognition model is downloaded once (about 20 MB) and then works offline.
• CSV export compatible with Pro Tools Post Swissknife, plus a clipboard-ready text version of the outstanding notes.
• RTP-MIDI / Apple MIDI MTC link over a standard IP network.
• Optional Android screen pinning through SCREEN LOCK, to reduce accidental trips to the home screen during a session.

Requirements

• Android 9 (API 28) or later.
• Android Studio with JDK 17 for development.
• An S Pen-compatible Android tablet is recommended.
• Network access is required only for the first OCR model download and for MTC networking.

Open and run in Android Studio

1. Clone the repository and open the repository root in Android Studio.
2. Let Gradle sync and install any missing Android SDK components.
3. Connect an Android device with USB debugging enabled, or select an emulator.
4. Choose the app configuration and press Run.

To produce an installable debug APK, use Build > Build App Bundle(s) / APK(s) > Build APK(s). Android Studio writes it to app/build/outputs/apk/debug/app-debug.apk.

Workflow

1. Create or open a project.
2. Start the timer, then tap + NOTE at each relevant moment.
3. Write with the S Pen and assign a department directly from the note card.
4. Pause to adjust the master timer or an individual note time code when needed.
5. Run OCR once the session is complete, correct any text if necessary, then use Share CSV from the project list.

Only unresolved notes are exported. Each unresolved note must have both a department and completed OCR before the CSV export is enabled.

MTC link

Enable LINK in a project before connecting from the Mac. On macOS, create or enable a network MIDI session in Audio MIDI Setup, then connect it to the tablet IP address shown by the app on UDP port 5004.

LINK uses RTP-MIDI / Apple MIDI on a normal IP network. Some console Ethernet networks are dedicated or do not pass RTP-MIDI, multicast, or UDP traffic. In that case, connect the Mac and tablet through a separate router, switch, or Wi-Fi network.

Screen lock

SCREEN LOCK ON requests Android screen pinning immediately. After Android has accepted it, the lock stays active while playback is running or paused, so the system does not show a confirmation on every Play/Resume action. Use the app's back arrow to return to the project list and choose SCREEN LOCK OFF to end it.

Screen pinning is controlled by Android; its availability and exact prompt vary by device policy and Android version.

Privacy and storage

Projects are JSON files in the app's private storage. Android backup and device transfer are disabled for this app. No project content is uploaded by Playback Notes Sync.

The first OCR run downloads Google's French Digital Ink model. After the model is present, recognition runs locally on the device.

CSV format

Exports are UTF-8 CSV files with CRLF line endings. The time code is emitted as a numeric MMSS value without colons. Department mappings used by the export are:

App department	CSV column
SFX	FX
CONC	CON
MIX, DIAL, STP, FOL, ADR	same name

Project layout

app/src/main/
  java/com/sebbedard/playbacknotes/
    data/       Project persistence and models
    export/     CSV generation and Android sharing
    ocr/        ML Kit Digital Ink wrapper
    sync/       RTP-MIDI / MTC implementation
    ui/         Compose screens, note cards, drawing canvas, and theme
  res/          App resources, FileProvider, and backup rules

Known limitations

• There is no undo/redo history yet.
• There is no pinch-to-zoom on the drawing canvas.
• Large numbers of detailed handwritten notes may be less fluid on older tablets.
• The OCR model is French-only at present.

Technology

• Kotlin 2.0.21
• Jetpack Compose / Material 3
• Android Navigation Compose
• Kotlin serialization and coroutines
• Google ML Kit Digital Ink Recognition
• Minimum SDK: 28 (Android 9)
• Target SDK: 34 (Android 14)