PocketLint

PocketLint is an Electron-based desktop application for Linux that manages an audio logical Y-split using PipeWire's virtual loopback devices. It allows you to record system audio while simultaneously routing it to physical outputs (e.g., speakers or headphones). Once recorded, the app post-processes the split channels, mixing them into a single-channel mono MP3 file, and uploads the audio to HeyPocketAI via their public API for transcription and processing.

Features

• PipeWire Logical Y-Split Management: Dynamically creates a virtual null sink (PocketLoopback) and loops its monitor output back to your choice of physical playback devices using PipeWire's Pulse compatibility layer.
• Audio Output Verification: Includes a "Test Output Sound" function to generate and play a 1-second synthesized tone through the loopback device to confirm physical audio routing before recording.
• Background Recorder: Captures raw system audio cleanly to temporary WAV files using native PipeWire tools (pw-record).
• Post-processing Pipeline: Uses FFmpeg to perform an FFT noise-reduction pass (afftdn) on each input stream, downmixes them to mono, and executes a dual-pass loudness normalization (loudnorm) before encoding to MP3. If either the microphone or system stream is silent, the loudness normalization is safely skipped to preserve dynamic range.
• Pocket AI Upload Pipeline: Connects with the HeyPocketAI API to request pre-signed S3 upload URLs and uploads the completed MP3 recording.
• Local Persistence & Retry Queue: Stores all recordings locally in ~/.config/pocketlint until they are successfully uploaded. Displays status indicators (Ready to sync, Processing, Syncing..., Synced, Failed) and allows manual retry for failed uploads.

Prerequisites

Ensure the following tools are installed on your Linux system:

• PipeWire (with pipewire-pulse compatibility)
• pactl (PulseAudio client controller)
• pw-record / pw-play (native PipeWire capture and playback tools)
• ffmpeg (used for generating test tones, noise reduction, loudness normalization, and MP3 encoding)

On Fedora/RHEL:

sudo dnf install pipewire-utils pulseaudio-utils ffmpeg

On Ubuntu/Debian:

sudo apt install pipewire-utils pulseaudio-utils ffmpeg

Getting Started

1. Clone the repository and navigate to the project directory:

   cd pocketlint

2. Install the Node.js dependencies:

   pnpm install

3. Start the application:

   pnpm start

Meeting App Setup

To record calls and meetings successfully without creating audio feedback loops or echo:

• Speaker / Output: In Zoom, Google Meet, Slack, or other meeting apps, select PocketLoopback as the speaker output.
• Microphone / Input: Select your Physical Microphone (do not select PocketRecordMix to avoid echo).

Local Storage Layout

The application saves configuration, the upload queue, and audio files in the Electron application user data folder:

• Config file: ~/.config/pocketlint/config.json
• Metadata Database: ~/.config/pocketlint/queue.json
• Audio Files: ~/.config/pocketlint/recordings/ (saved as .mp3 files after post-processing)