# Audio Trimmer

> Cut a section out of an audio file with millisecond accuracy. Waveform display with selection overlay, inline preview before download, keyboard shortcuts.

Canonical: https://helpers.aibrush.co/en/audio-trimmer

## What it does

Drop an audio file. The waveform renders in a canvas with peaks downsampled to 1024 buckets — large files (up to an hour) load without freezing the tab. The selected range highlights in the waveform so you can see exactly what you're cutting.

Inline audio player lets you scrub the source. I/O hotkeys set the selection start/end at the playback head. K plays / pauses.

## How to use it

1. **Drop the audio file** — Waveform renders within a second or two. Decode runs in your browser.
2. **Mark in/out** — Play to the spot, press I to set the in point. Continue to the end, press O to set the out point. Or type timecodes directly.
3. **Process and preview** — The trimmed audio plays inline. Download once you're happy with it.

## When to use it

### Podcast snippets

Pull a 30-second highlight from a 90-minute episode for social posts.

### Ringtones

Cut the catchy chorus out of a song for a phone ringtone (subject to copyright).

### Voice memo cleanup

Trim the silence at the start/end of a Voice Memo recording before sharing.

## FAQ

### Why doesn't the waveform render?

Some codecs (Opus in very old containers) don't decode via the browser's AudioContext. The timecode fields still work even when the waveform doesn't.

### Is the trim millisecond-accurate?

Yes — output is frame-accurate (audio frames, ~20ms for typical AAC). The timecode input accepts millisecond precision.