This guide explains how to use the iNatSpectro Chrome Extension after it’s been installed in Google Chrome. It adds a powerful, interactive spectrogram and waveform view to audio recordings on iNaturalist observation pages.
Overview
This extension helps identify wildlife calls by visualizing their acoustic structure. It works directly on iNaturalist pages with audio and automatically shows a spectrogram and waveform beneath the built-in audio player.
It includes:
- Automatic spectrogram rendering
- Waveform view (volume over time)
- Spectrogram view (frequency over time, color-mapped by loudness)
- Zoom and pan controls
- Auto-selected species profiles
- Advanced tuning options
What to Expect
When you visit an iNaturalist observation with an audio file:
- A new visual panel appears below the audio player.
- This panel shows:
- A waveform (white), representing loudness over time.
- A spectrogram (color), representing pitch and intensity over time.
- The spectrogram is automatically rendered once the page and audio load.
How to Use It
1. Open an iNaturalist Observation with Audio
- Visit https://www.inaturalist.org
- Search for an observation with a sound recording (look for an audio player).
- Open the observation’s detail page.
2. View the Spectrogram Automatically
- If the audio file is 60 seconds or shorter, the spectrogram is automatically generated as soon as the page finishes loading.
- For longer audio files, you will see a message and a button labeled “Render Full Spectrogram”.
- Click this button to analyze and render the full visualization.
3. Zoom and Pan
- Use the Zoom slider (or your mouse scroll wheel) to zoom in on the waveform and spectrogram.
- Click and drag to pan left or right across the timeline.
- A yellow line shows the current playback position while audio is playing.
4. Profile Selection
- The extension auto-selects a profile based on the identified species. Supported profiles:
- Bat – for high-frequency echolocation
- Frog – for choruses and croaks
- Bird – for tonal bird songs
- Insect – for high-pitched stridulation
- Cetaceans – for underwater low-frequency calls
- General – for broad-spectrum analysis
- If the automatic profile doesn’t seem appropriate, you can change it using the Profile dropdown above the spectrogram.
5. Customize Parameters
- Click the ⚙️ gear icon to open the advanced controls panel.
- You can fine-tune the spectrogram display by adjusting:
- Min/Max Frequency
- Window (dB) – affects contrast
- Gamma – adjusts brightness scaling
- Percentile – adjusts dynamic range calculation
- Smoothing – smooths out noisy visuals
- Click “Reset to Profile Defaults” to return to the selected profile’s default settings.
Interpreting the Spectrogram
- X-axis: Time (seconds)
- Y-axis: Frequency (Hz or kHz)
- Color intensity: Loudness (brighter = louder)
The spectrogram lets you visually detect chirps, croaks, pulses, harmonics, and patterns in wildlife calls that can be hard to hear.
Tips for Effective Use
- Use the Bird, Frog, or Bat profiles to highlight different frequency ranges.
- For dense frog choruses or quiet bird calls, adjusting Window (dB) and Gamma can help.
- For ultrasonic bat calls, try zooming in and tweaking frequency limits up to 120 kHz.
- Combine the waveform view and playback audio to correlate what you hear with what you see.
Known Limitations
| Limitation | Description |
|---|---|
| Long audio files (> 60 sec) | Require clicking Render Full Spectrogram manually |
| External or embedded audio | Audio must be hosted natively on the iNaturalist page |
| Mobile layout | Best viewed on desktop for full controls and visibility |
Troubleshooting
| Problem | Solution |
|---|---|
| Spectrogram doesn’t show | Wait for the page and audio to fully load |
| Spectrogram is blank or low-contrast | Try switching profiles or adjusting Gamma and Window (dB) |
| Zoom/pan doesn’t work | Ensure full spectrogram is rendered first |
| Wrong profile applied | Manually select a different one from the dropdown |
Feedback and Development
This extension is built for field naturalists, researchers, and citizen scientists. Your feedback is valuable!
- Report issues or make suggestions via the Chrome Web Store listing.
- Contributions to development and improvement are welcome.
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