audioscope

Audio inspector for waveform, spectrogram, playback, loop selection, loudness, and metadata review.

Quick Start

1. Install the extension.
2. Open a supported audio file.
3. If needed, run audioscope: Open Active Audio File in audioscope.

What it does

audioscope is a read-only custom editor for audio files inside VS Code.

• Open supported audio files in a dedicated audio editor
• Inspect synchronized waveform and spectrogram views
• Switch between spectrogram, mel-spectrogram, MFCC, scalogram, and chroma analysis
• Seek with the timeline or -5s / +5s buttons
• Control playback speed from 0.5x to 2x
• Zoom the waveform, follow playback, and set loop ranges by dragging
• Review metadata such as codec, container, duration, sample rate, bitrate, channels, tags, and chapters
• View loudness summary values including integrated LUFS, LRA, sample peak, and true peak
• Use bundled FFmpeg and ffprobe WASM tools, so no system ffmpeg install is required at runtime

[!NOTE] VS Code Media Preview can still take precedence for some extensions on first open, especially .mp3, .wav, and .ogg files.

Supported Formats

.wav, .wave, .mp3, .ogg, .oga, .flac, .m4a, .aac, .opus, .aif, .aiff

Features

Waveform and transport

• Synchronized waveform viewer
• Timeline scrubber and overview strip
• Play / pause controls
• Seek backward and forward by 5 seconds
• Playback speed control
• Follow playback mode
• Loop selection and loop handles
• Waveform zoom controls

Spectrogram and analysis

• Spectrogram visualization
• Audio analysis uses WebGPU when available, with WASM fallback for unsupported environments
• Spectrogram, mel-spectrogram, MFCC, scalogram, and chroma analysis are computed from a mono downmix of the source audio
• Mel-spectrogram analysis
• MFCC analysis
• Scalogram analysis
• Chroma analysis
• FFT size controls
• Overlap ratio controls
• Window function selection
• Frequency scale controls
• Colormap distribution controls
• Decibel range controls
• Mel band count controls
• MFCC coefficient controls
• Scalogram omega0 control
• Advanced scalogram frequency range and row density defaults via audioscope.spectrogramDefaults

Metadata and loudness

• Audio metadata summary
• Codec name and long name
• Container / format information
• Duration, size, bitrate, sample rate, and channel layout
• Tags and chapter data
• Loudness analysis with LUFS, LRA, Peak, and True Peak
• FFmpeg / ffprobe tool status and fallback guidance

Settings

• audioscope.spectrogramQuality: balanced | high | max
• audioscope.spectrogramDefaults: persisted defaults for analysis controls, including advanced scalogram defaults when edited in settings JSON
• audioscope.openSampleOnStartupInDevelopment: open the bundled sample on startup in development mode

Keywords

audio inspector, waveform, spectrogram, mel, mfcc, scalogram, chroma, playback, loop, metadata, loudness, LUFS, integrated LUFS, EBU R 128, LRA, mp3, wav, flac, m4a, ogg, aac, opus, aiff, aif

Development

Build prerequisites:

• bun
• zig 0.15+
• Emscripten toolchain
• FFmpeg submodule checkout

Build from source:

bun install
git submodule update --init --recursive
bun run compile

The full build compiles:

• embedded FFmpeg / ffprobe WASM tools
• analysis WASM binaries
• webview bundles
• extension host output

Third-Party And Vendor Code

This repository includes a small amount of vendored and third-party source used to build the shipped extension and WASM tools.

• src-wasm/third_party/ffmpeg The FFmpeg source tree vendored as a submodule and used to build the embedded FFmpeg / ffprobe WebAssembly binaries. Upstream repository: https://github.com/FFmpeg/FFmpeg
• src-wasm/third_party/pffft PFFFT and FFTPACK-based FFT code used by the analysis WASM runtime. Original PFFFT repository: https://bitbucket.org/jpommier/pffft/
• src-webview/vendor/SignalsmithStretch.mjs Vendored Signalsmith Stretch Web module used for time-stretch playback in the webview transport path. Official upstream: https://signalsmith-audio.co.uk/code/stretch.git GitHub mirror: https://github.com/Signalsmith-Audio/signalsmith-stretch

Licensing and attribution details for bundled third-party code are documented in THIRD_PARTY_NOTICES.md. FFmpeg rebuild notes and revision details are documented in FFMPEG_SOURCE.md.

License

MIT