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Audio Waveform Generator

Turn locally decoded audio into a deterministic, scalable SVG peak waveform with exact dimensions, colors, and an inspectable download.

Privacy: your files never leave your device. All processing happens locally in your browser.

How to use

  1. 1.Choose one browser-decodable audio file within the stated compressed and decoded limits.
  2. 2.Set the SVG width, height, background color, and waveform color, then generate the local peak envelope.
  3. 3.Check the reported frames and peak-column count, inspect the preview or SVG text, and download the exact scalable SVG.

About Audio Waveform Generator

Audio Waveform Generator creates a static SVG overview from audio decoded in the current browser tab. Choose a supported file, set a width from 320 through 1,600 pixels and a height from 120 through 600 pixels, choose background and waveform colors, and generate an image that can be inspected, downloaded, scaled, and opened in an SVG-aware editor. No audio file or generated graphic is uploaded to Lizely.

The visualization uses a deliberately simple peak-envelope method. The decoded sample frames are divided into equal index ranges. For each range, the tool finds the minimum and maximum finite sample across every decoded channel, clamps defensive out-of-range values to -1 through 1, and draws one vertical SVG line from the bucket maximum to its minimum. This preserves short positive and negative peaks more honestly than taking one arbitrary sample per bucket. It does not calculate frequency content, beats, notes, loudness, speech, transients, or musical structure.

The number of columns is the smaller of the requested image width, 1,000, and the decoded frame count. A short clip therefore does not invent more independent measurements than it contains, while a long clip stays within a bounded SVG and processing budget. Bucket boundaries use integer frame indices derived from each bucket number and total frame count. The first bucket begins at frame zero, the last bucket reaches the final decoded frame, and accepted frames are not omitted between adjacent ranges.

For multichannel audio, the image is a combined peak overview. A bucket can take its minimum from one channel and its maximum from another. The result does not display separate left and right lanes, preserve channel identity visually, or average channels into a new audio signal. The original audio is never rewritten. If separate channel waveforms are required, use an audio editor that exposes each channel as its own track.

SVG coordinates are deterministic. The vertical center is half the requested height, and full-scale positive or negative samples extend to 45 percent of the height above or below that center. This leaves a five-percent margin at the top and bottom. Columns are evenly centered across the requested width. Colors must come from the browser's six-digit hexadecimal color controls, and all SVG markup is generated from validated numbers and those colors rather than copied from filenames or embedded source metadata.

Processing stays local. Web Audio reads the selected MP3, WAV, M4A, AAC, Ogg, WebM, or FLAC only when the current browser and operating system support its real codec. An extension or MIME label cannot guarantee decoding. Unsupported, corrupt, empty, or disguised files return an error. Selecting a replacement file, changing an option, generating again, or leaving the page revokes the obsolete object URL so an older image cannot appear to represent new inputs.

The same decoded-data limits used by the site's audio tools apply here. The compressed file must be at most 50 MiB. Decoded audio must last no more than five minutes, contain one through eight channels, use a rate from 8,000 through 192,000 Hz, and remain within 30 million channel samples. These checks matter because a small compressed file can expand into much larger floating-point channel arrays. Over-limit audio is rejected as a whole; the waveform is not silently made from only the beginning.

The download is text-based SVG, not PNG, JPEG, video, or audio. It contains one background rectangle and a group of peak lines with fixed pixel dimensions and a matching viewBox. SVG stays sharp when placed at another display size, but extremely large print or editing workflows may still require different stroke widths or more detailed source data. The page shows the exact generated SVG text in an expandable inspector, and the download uses that identical string.

A peak waveform is not a calibrated loudness meter. Two recordings can show similar peaks while sounding very different because perceived loudness depends on duration, frequency balance, dynamics, and playback conditions. It is also not a spectrogram: time runs left to right, but the vertical line represents sample amplitude range, not frequency. Do not use the picture to diagnose hearing, equipment, clipping history, phase, or mastering compliance.

The implementation is classified as product-defined rather than a reference-data table. Tests directly prove mono and stereo bucket boundaries, cross-channel extrema, non-finite defensive handling, full-scale clipping, exact SVG coordinates, dimensions, colors, invalid inputs, and filenames. Browser verification supplies a known WAV, confirms the decoded frame count and column count, downloads the SVG, parses its dimensions and line count, and checks selected coordinates. That gives a reproducible truth path without claiming that this envelope is the only standardized way to depict audio.

Methodology & sources

Decode one bounded local audio file with Web Audio and reject invalid rate, duration, channel, byte, or 30-million-channel-sample budgets. Divide all decoded frames into min(width, 1000, frames) contiguous integer-index buckets. For each bucket, take the finite clamped minimum and maximum across every channel. Map full scale to 45% of the requested height around the vertical center and place one peak line at each evenly spaced horizontal bucket center. Generate a validated-color SVG containing one background rectangle and the exact line set; preview and download share the identical string and stale URLs are revoked.

Frequently asked questions

Is this a spectrogram or frequency analyzer?
No. It draws time-domain minimum and maximum sample peaks per bucket. It does not show frequency, notes, beats, or calibrated loudness.
How are stereo and multichannel files shown?
Each bucket uses the minimum and maximum across all accepted channels, creating one combined peak overview rather than separate channel lanes.
Are the audio file and waveform uploaded?
No. Browser decoding, peak extraction, SVG generation, preview, and download all happen in the current tab.

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