# Real-time Speech Recognition with Vosk and Zig

This project implements a minimal real-time speech-to-text application using Vosk and Zig.

## Audio Device Configuration

The application uses ALSA's default device, which is configured in `alsa.conf`. To use a different audio device:

1. Find your audio devices: `aplay -l` or `arecord -l`
2. Edit `alsa.conf` and update the `pcm.!default` section:
   ```
   pcm.!default {
       type hw
       card 3      # Change to your card number
       device 0    # Change to your device number
   }
   ```
3. Rebuild and run the application

### Prerequisites
- Zig 0.15.1 (configured via mise)
- Nix development environment configured for ALSA, and audio libraries
- patchelf (for fixing RPATH in release builds): `nix-env -iA nixpkgs.patchelf`

### Vosk Model Download
The application uses the Vosk small English model for speech recognition:
- **Source**: https://alphacephei.com/vosk/models/vosk-model-small-en-us-0.15.zip
- **Size**: ~50MB
- **Language**: English only
- **Accuracy**: Good for simple sentences and commands

### Installation Steps
1. Enter nix development environment: `nix develop`
2. Build application: `zig build`
3. Run: `zig build run`

### Release Builds and Portability

When building in release mode (`-Doptimize=ReleaseSafe`), Zig embeds the full path to libvosk.so in the ELF NEEDED entries, making the binary non-portable. The build system automatically fixes this by running `fix_needed.sh` which uses `patchelf` to replace the full path with just the library name.

**Automatic fix**: Just run `zig build -Doptimize=ReleaseSafe` - the NEEDED entries are fixed automatically.

**Manual fix**: If needed, you can run `./fix_needed.sh [binary_path] [library_name]` manually.

The script uses `patchelf` (via nix-shell if not installed) to replace entries like:
- Before: `NEEDED: [/home/user/.cache/zig/.../libvosk.so]`
- After: `NEEDED: [libvosk.so]`

This makes the binary portable while using the existing RPATH (`$ORIGIN/../lib`) to find the library at runtime.

## Usage
The application will:
- Initialize audio capture from default microphone
- Load the Vosk speech recognition model
- Process audio in real-time
- Output recognized text to terminal
- Exit on Ctrl+C

## Dependencies
- Vosk C API library
- ALSA for audio capture

## Notes

Vosk tends to recognize "light" as lake or like