CallVault is a self-contained, privacy-focused call recorder that captures, transcribes, and summarizes phone and VoIP app calls entirely on your device. By utilizing embedded ADB or Shizuku for shell-level audio capture, it processes everything locally without relying on cloud servers.
Technical Overview of CallVault
The application secures shell-level audio capture privileges either through its embedded ADB client via wireless debugging or by integrating directly with an existing Shizuku environment. For post-call processing, it leverages local CPU execution using whisper.cpp for multi-language transcription and llama.cpp with Google's Gemma model to generate detailed offline summaries.
Core Features of CallVault
- Universal call capture for standard phone calls and select VoIP applications including WhatsApp, Signal, and Telegram.
- On-device AI summaries powered by a downloadable Gemma model to extract key points, decisions, and action items locally.
- Local offline transcription utilizing whisper.cpp across 13 languages, functioning completely offline and supporting full-text search.
- Automated speaker labeling that separates dual-channel audio into distinct participant identities without requiring secondary voice models.
Compatibility & Quick Setup
Requires Android 11+ (arm64-v8a) — install the APK and grant shell privileges via Shizuku or the built-in wireless debugging wizard.