MR. BLINDBANDIT / CREATOR TOOLS

BPM Tap & Markers

Tap tempo, stamp markers on the playhead, export JSON.

Ready to choose a file. Engine loads on demand.

Technical details

Browser-local FFmpeg WebAssembly worker, Canvas and Web Audio. Single-worker fallback does not require SharedArrayBuffer. Files are not retained after reload.

How to use this tool

Choose your source file using the labeled file button.
Review metadata, preview and the relevant destination settings.
Start processing and keep this page open.
Download or share your finished file from the completion dialog.

Supported files and device limits

Common audio inputs include MP3, WAV, FLAC, M4A/AAC, OGG and Opus when the bundled engine can decode the codec. Images: JPEG, PNG and WebP. Convert HEIC to JPEG first. Large sources, long podcasts and 4K exports can exceed browser memory. Try a shorter clip or lower resolution if an export fails.

Privacy and troubleshooting

Source media stays in this browser session. The engine downloads from jsDelivr on first use; the provider receives ordinary connection information but no source media from these tools. Only non-sensitive destination preferences are saved locally. Retry after an engine error, close memory-heavy tabs or try a different browser. No higher-resolution setting can restore detail absent from your source.

Accessibility

Controls have text labels, timelines use numeric time fields, and downloads open in a keyboard-accessible dialog. Accessibility information and issue reporting.

Finding tempo and marking moments

Tap along to the beat to estimate tempo in beats per minute, and drop markers at the playhead to note sections such as verses, drops or edit points. Markers export as JSON for your own notes or editor scripts.

Step by step

Choose a file and start playback.
Tap on each beat for several bars; the estimate becomes more accurate as you tap.
Add markers at important moments.
Export the markers as JSON.

Tips

Tap for at least eight beats for a stable reading.
Half-time or double-time readings are common; choose the one that feels right.
Use markers with the chapter markers tool to build navigation for long audio.

Screen-reader tips: every control has a text label, and progress and completion messages are announced in a live region, so you can keep your focus where it is. Use the heading keys to jump between the file, settings and results sections. Your file is processed in this browser and is not uploaded to the server; it is gone when you reload the page. See all media tools and the media suite terms.