Overview
Samsung's built-in call recorder isn't available on every phone sold in Pakistan, and the recorder apps on the Play Store only capture your side clearly. Since Android 10 they can't reach the call audio, so they record through the microphone and the other person comes out faint.
CallVault records the call audio itself. It's built for everyday Pashto and Urdu calls, where you want a clean record of both voices.
Download CallVault · Source code · How it works, in detail
How it works
- Call audio without root. Android grants call-audio capture to the ADB shell user. CallVault runs its recorder in a shell process through Shizuku, so the phone's normal security stays intact and Knox is never tripped.
- SIM and WhatsApp calls. Regular calls use the voice-call stream. Wi-Fi Calling and WhatsApp calls combine the microphone with a capture of the call's playback audio.
- Automatic. Recording starts when a call connects and stops when it ends. That includes a fix for One UI, which doesn't always report when a call ends.
- Player and manager. Recordings are grouped by day and by person, searchable by name or number, and play at up to 2x. You can share or delete them one at a time or in bulk.
- Private by design. The app has no internet permission. Recordings are small Opus files in a folder you choose.
Stack
Kotlin and Jetpack Compose, Shizuku, MediaCodec/MediaMuxer for Opus encoding, and the Storage Access Framework for files. CallVault is a GPL-3.0 fork of ShizuCallRecorder by kitsumed.
My role
I researched how existing recorders capture calls and chose the Shizuku shell approach. I hardened the recording engine against race conditions and Samsung-specific bugs, tested it on a Galaxy S26 Ultra running Android 17, and built the recordings player and person folders.