# Go Two-Tone Detector

This project is a Go application for detecting two-tone sequences (such as paging tones) in real-time audio streams. It connects to an RTSP stream, decodes G711 mu-law audio, and analyzes the audio for specific tone patterns using the Goertzel algorithm. When a valid two-tone sequence is detected, the app can record and save the relevant audio segment as a WAV file.

## Features

- **RTSP Client:** Connects to audio streams using RTSP protocol.
- **G711 mu-law Decoding:** Converts mu-law encoded audio to PCM samples.
- **Two-Tone Detection:** Uses Goertzel algorithm to detect and confirm tone sequences.
- **Recording:** Automatically records and saves audio segments containing detected tones.
- **Configurable Parameters:** Window size, hop size, thresholds, and durations are adjustable via command-line flags.
- **Graceful Shutdown:** Handles interrupts and ensures recordings are saved before exit.

## Usage

```sh
go run main.go -rtsp <RTSP_URL> [flags]
```

### Example Flags

- `-rtsp` : RTSP stream URL (required)
- `-winMs` : Window size in milliseconds (default: 100)
- `-hopMs` : Hop size in milliseconds (default: 50)
- `-ratioThresh` : Power ratio threshold for tone detection
- `-rmsThresh` : RMS threshold for signal detection
- `-minAms` : Minimum duration for Tone A (ms)
- `-minBms` : Minimum duration for Tone B (ms)
- `-gapMaxMs` : Maximum allowed gap between tones (ms)
- `-silenceThresh` : RMS threshold for silence detection
- `-silenceDurMs` : Duration of silence before stopping recording (ms)

## Output

- Detected tone events are logged to the console.
- Audio segments containing detected tones are saved as WAV files in the current directory.

## Requirements

- Go 1.20+
- [gortsplib](https://github.com/aler9/gortsplib)
- [go-audio/wav](https://github.com/go-audio/wav)

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