Draw a waveform image

Draw an audio file's (or a video's audio track's) peaks as a PNG, one column per pixel of width, decoded through the same PCM path as audio-reverse and drawn straight into a pixel buffer, the way font-preview rasterizes glyphs, with no canvas. WAV decodes everywhere; other codecs need a browser.

Draw a waveform image turns a clip's peaks into a PNG, one bar per pixel of width, at 800 by 200 pixels by default in a colour you pick. Decoded PCM samples go directly into a bitmap, skipping any canvas API. WAV opens in Node and the browser; every other codec needs a browser tab first.

Questions

What determines the shape drawn?

For every pixel column, the tool finds the minimum and maximum peak sample within that slice of time and draws a vertical bar between them, the standard peaks style of waveform.

Can I change the size or colour?

Yes. width and height default to 800 by 200 pixels, and color takes a 6 digit hex code like #3b82f6, the default blue used here.

Why is there no canvas involved?

Because the pixel buffer is written directly, the same rasterizing approach font-preview uses for glyphs, so this can run without OffscreenCanvas.

Does it work on a video file?

Yes, on its audio track. Only the audio is decoded and drawn; the video picture itself is not read.

What image format do I get?

Always PNG, named after your source file with -waveform.png on the end.

Related Video tools

n→nConvert audioChange an audio file between MP3, WAV, FLAC, Ogg and M4A (AAC). In the browser only, like video-convert, because mediabunny decodes and encodes through WebCodecs, which Node has no equivalent of.n→nNormalize audio volumeScale an audio (or video's audio track) so its loudest sample hits a target peak level: a two-pass peak scan followed by a gain-scaled re-encode, both through WebCodecs, so this runs in the browser only, like video-convert. Always outputs MP4 with an unchanged video track (if any).n→1Trim or merge audioCut an audio file down to a start-end range, or concatenate two or more audio files one after another. A packet-level copy with no decoding, so this runs in Node, the CLI and MCP as well as the browser. Output is always an MP4 audio file (.m4a).n→nExtract audio from videoPull the audio track out of a video into its own MP4 audio file. A packet-level copy with no decoding or re-encoding, so this runs in Node, the CLI and MCP as well as the browser.n→nMute videoDrop the audio track from a video, keeping the picture untouched. A packet-level copy of the video track only, no decoding, so this runs in Node, the CLI and MCP as well as the browser.n→nReverse audioPlay an audio file (or a video's audio track) end to start, decoded to raw samples and re-encoded as WAV. WAV input decodes in Node, the CLI and MCP as well as the browser, the same PCM path audio-trim-merge's packet copy sits next to; AAC, MP3, Opus, FLAC and Vorbis need a browser.n→nFade audio in or outRamp an audio file's (or a video's audio track's) volume up from silence at the start, down to silence at the end, or both, linear or logarithmic, decoded and re-encoded as WAV through the same PCM path as audio-reverse. WAV decodes everywhere; AAC, MP3, Opus, FLAC and Vorbis need a browser.n→nConvert mono to stereo or backChange an audio file's (or a video's audio track's) channel count: average every channel down to mono, duplicate a mono track into identical left and right channels, or swap left and right, decoded and re-encoded as WAV through the same PCM path as audio-reverse. WAV decodes everywhere; other codecs need a browser.