Audio Waveform Generator

No. The file is read into an ArrayBuffer in your browser, decoded with the Web Audio API, downsampled to peaks, and rendered to a Canvas. None of the audio bytes are sent over the network. You can verify with DevTools > Network: no outbound requests for the audio.

A peak waveform is a compact visual representation of an audio file: the original ~44,100 samples per second are summarised into a few thousand "buckets", and each bucket records the loudest sample inside it. SoundCloud, Audacity and most DAWs use this exact approach for their preview strips. It is fast to compute and visually informative without storing every sample.

The audio is probably very quiet relative to its peak (low average loudness, high dynamic range). The visualization scales to the absolute peak, so if the loudest moment is 0.1 the rest looks tiny. If you want a more "filled" waveform run the audio through a normalizer or compressor first - or pick a louder section of the file.

PNG is a raster image - fixed pixel grid, compact, best for fixed-size embeds (blog hero, podcast thumbnail). SVG is vector - scales to any size without blur, smaller for simple shapes, editable in Illustrator and Figma. For social media and YouTube thumbnails pick PNG. For a logo treatment or a poster pick SVG.

Up to 4096 px in this tool, which suits 4K thumbnails. The downsample step uses ~2,000 buckets regardless of width, so going wider just stretches the bars. For ultra-wide or animated visualizations export SVG and scale it.

The Web Audio API decodes the entire file into uncompressed samples in memory before peaks can be extracted. For a 1-hour MP3 that is roughly 600 MB of float32 audio. Browsers do this on a worker thread but it still takes 5-15 seconds for long files. Smaller MP3s decode in under a second.

This tool generates a static peak image of the whole file. For real-time visualization (bouncing bars during playback) you would need an AnalyserNode hooked into Web Audio and an animation loop - that is a different workflow. We may ship a separate tool for it if there is demand.

No - the Web Audio API decodes audio formats only. To generate a waveform from a video, first extract the audio using the <a href="/tools/extract-audio-from-video/">extract audio from video</a> tool and feed the resulting MP3 or WAV here.