iNatSpectro by Japh

iNatSpectro v3.6.1

Visualise Nature's Sounds on iNaturalist

This extension adds a dynamic spectrogram visualisation beneath audio recordings on iNaturalist.org observation pages. Whether you're identifying frog calls, bat echolocation, bird songs, or insect stridulation, this tool lets you see what you're hearing. 🎵

🎧 Why use it?
Many wildlife sounds are easier to interpret with visual context — especially in noisy environments or when calls are hard to distinguish by ear. A spectrogram lets researchers, identifiers, and curious naturalists analyse recordings at a glance, spotting patterns that ears alone can miss.

🔬 How it works
The extension uses the Web Audio API to render a spectrogram whenever you play an audio file on an iNaturalist observation. It loads automatically and blends seamlessly into the existing page. All processing happens locally in your browser — no data is ever collected or transmitted.

🔍 Features in v3.6.1:
• Automatic spectrogram loading — appears instantly on observation pages
• Automatic taxon-based profile selection (bat, bird, frog, insect, cetacean, general) — all six profiles freshly retuned against real iNaturalist recordings 🐸🦇🐦🐋
• Full spectrum analysis, including ultrasonic frequencies up to 384 kHz for bat research
• Sharper rendering on high-DPI and Retina screens with device pixel ratio awareness
• Peak decimation rendering — short calls that previously fell between sampled columns are now always visible; no signal energy is dropped
• Improved frequency-axis resolution — frequency bins are now handled correctly on log and mel scales, so high-frequency detail is crisp rather than smeared
• Percentile-based normalisation — noise floor and signal peak are set robustly, calibrated against Sonic Visualiser reference renders, so recordings with codec artefacts or outlier levels still look great
• Faster rendering via a precomputed gamma lookup table — visually identical output, significantly less CPU work
• Higher frequency resolution — the analysis window cap is removed, giving ~47 Hz/bin at 48 kHz with the default FFT size (previously limited to ~120 Hz/bin)
• Enhanced zoom — smooth zooming from 100% to 2000% with progressive high-resolution rendering
• Multiple frequency scales — logarithmic, linear, and mel (perceptual)
• Configurable high-resolution rendering (50–800 pixels/second) with automatic performance optimisation
• Interactive controls — 7 adjustable parameters for brightness, frequency range, smoothing, and resolution
• Advanced caching with LRU eviction for snappy performance
• No tracking, no telemetry — built specifically for the iNaturalist community 🌿

🧬 Perfect for:
• Citizen scientists and professional biologists
• Bat, frog, bird, insect, and cetacean call analysis
• Educators and ecoacoustics enthusiasts
• Research-grade bioacoustic work up to 384 kHz
• Anyone who wants to bring audio observations to life visually

🚀 What's new in v3.6.1:
The headline changes are all about rendering fidelity and accuracy. Peak decimation now guarantees that every short call is captured — no more signals slipping between sampled columns. Frequency-axis handling is corrected for log and mel scales. Normalisation is percentile-based and robust against tricky recordings. The analysis window cap is gone, so frequency resolution is dramatically improved. All six species profiles have been retuned from scratch using a new automated optimisation tool and real iNaturalist data. High-DPI screens now render sharper spectrograms. And a precomputed gamma LUT makes all of this faster than before.

iNatSpectro integrates seamlessly into iNaturalist, respects your privacy, and helps you get more from every audio observation — visually. Version 3.6.1 is the most accurate and detailed release yet. 🔭