Synthetic Bird Song

Synthetic bird songs can be made by defining a set of time-frequency-amplitude points, that are stored in a JSON format file.

The JSON file can be loaded in the Main Menu under File->Load JSON. Below is a synthetic Yellow-browed Warbler song loaded from the JSON file discussed further below. Surprisingly, the bird detection algorithm correctly detects this as a Yellow-browed Warbler.

The JSON file has the following elements

• Name: the name of the synthetic bird song.
• Sample Rate: typically 48000, 44100 or 96000 kHz.
• Chirp duration: time duration in seconds of a chirp.
• Repeat: number of times to repeat the chirp.
• Prepadding and Postpadding: blank sections before and after the concatenated chirps.
• Global Noise: backgound noise that is super-imposed on the recording. Options are "Forest", "Brown", "White" and "Pink".
• Segments: consists of a series of Points list. In this example, there is only one segment, and it consists of list of 7 time-frequency-amplitude points of Type "wave".
• Type: Waveform types include "wave", "wave_harmonic", "wave_twotone","freq_jitter" and "silence".

The total length of the recording is given by:

• totalChirpDuration = chirpDuration * repeatCount;
• finalDuration = prePad + totalChirpDuration + postPad;

{
  "Name": "Synthetic_Yellowbrowed_Warbler",
  "SampleRate": 48000,
  "ChirpDuration": 1.95,
  "Repeat": 3,
  "PrePadding": 0.5,
  "PostPadding": 0.2,

"GlobalNoise": {
  "Enabled": true,
  "Type": "Forest",
  "Amplitude": 0.05,
  "HighPassHz": 80
  },

  "Segments": [
    {
     "Points":[
       { "Time": 0.15, "Frequency": 6500, "Amplitude": 1 },
       { "Time": 0.18, "Frequency": 6000, "Amplitude": 1 },
       { "Time": 0.20, "Frequency": 6000, "Amplitude": 1 },
       { "Time": 0.26, "Frequency": 4500, "Amplitude": 1 },
       { "Time": 0.29, "Frequency": 5200, "Amplitude": 0.5 },
       { "Time": 0.32, "Frequency": 5200, "Amplitude": 1 },
       { "Time": 0.38, "Frequency": 7400, "Amplitude": 1 }],
      "Type": "Wave"
    }
  ]
}

Above shows an advanced option (not yet available) where the JSON file is automatically created by tracking a real recording of a bird-song.. This JSON file contains time-frequency-amplitude triplets sampled every millisecs, so it consists of several thousand lines. The higher sampling rate allows to give better respresentation of the amplitude variations, and the subtle changes in frequency.

For more information on JSON format, check out this link https://www.json.org/json-en.html