Rustic_Audio

Rustic_Audio is a voice recorder application with a DSP effects chain for audio cleaning, and an Opus encoder for outputing highly compressed audio files for use in low-bandwidth communication. This project is licensed under the GPL-3.0 License. This work is supported by the NLnet foundation, and intended for use in the Katzen messenger, as well as any project that needs it.

Features

• Record audio from the default input device
• Apply DSP effects for audio cleaning
• Encode processed audio to Opus
• Playback original and processed audio

DSP Effects and Settings

The DSP effects chain includes the following effects:

1. Root Mean Square (RMS) Normalization

   • changes input loudness of recording to target loudness

2. Filters

   • Highpass Filter: Removes frequencies below a certain threshold.
     • highpass_freq: Frequency threshold in Hz (20.0 - 1000.0 Hz)
   • Lowpass Filter: Removes frequencies above a certain threshold.
     • lowpass_freq: Frequency threshold in Hz (1000.0 - 20000.0 Hz)

3. Spectral Gate

   • Fast Fourier Transform (FFT) noise reduction.
     • threshold_db: Threshold in dB (-50.0 - 24.0 dB)

4. Noise Gate

   • Reduces noise by applying a threshold to the amplitude.
     • amplitude_threshold_db: Threshold in dB (-60.0 - 0.0 dB)
     • amplitude_attack_ms: Attack time (0.1 - 100.0 ms)
     • amplitude_release_ms: Release time (1.0 - 1000.0 ms)
     • amplitude_lookahead_ms: Lookahead time (0.0 - 20.0 ms)

5. Gain Booster

   • Increases the amplitude of the audio signal.
     • gain_db: Gain in dB (0.0 - 24.0 dB)

6. Lookahead Limiter

   • Limits the amplitude of the audio signal to prevent clipping.
     • limiter_threshold_db: Threshold in dB (-12.0 - 0.0 dB)
     • limiter_release_ms: Release time in milliseconds (10.0 - 500.0 ms)
     • limiter_lookahead_ms: Lookahead time in milliseconds (1.0 - 20.0 ms)

Dependencies

• Audiopus (Opus decoding and playback)
• CMake (for Opus Encoding)
• ALSA (API for accessing audio devices on Linux)

Linux Debian/Ubuntu-based Dependencies Installation

sudo apt-get install libasound2-dev pkg-config
sudo apt-get install libopus-dev

License

This project is licensed under the GPL-3.0 License. See the LICENSE file for more details.