I built a free ringtone maker with Web Audio and FFmpeg.wasm

Description and use

Ringtone Cropper is a free web tool that lets users quickly trim a 30‑second audio clip and export it as a ringtone for Android or iPhone, running entirely in the browser.

Problem

Users need a quick way to create ringtones from any audio or video file without installing software.

Outcome

Ringtone Cropper provides a 30‑second ringtone creation workflow that runs entirely in the browser, preserving audio quality and avoiding server‑side storage.

Workflow

• Upload audio or video file
• Select a moment on the waveform (default 30 s, presets 15/30/40 s or custom)
• Preview the selection with optional fade‑in/out and loudness normalization
• Export to MP3, M4A, M4R, or WAV using ffmpeg.wasm
• Download the file and set it as a ringtone on phone

Evidence

Upload an audio or video file, select a moment on the waveform, preview it, and export.

Source

The frontend is plain HTML, CSS, and JavaScript. Web Audio handles decoding and preview, while ffmpeg.wasm handles export in the browser.

Source

Optional YouTube imports take a different path: a Cloudflare Worker validates and rate-limits the request, then a container running yt-dlp retrieves the audio.

Source