How the Audio Volume Booster Works
AnyTool adjusts loudness in two stages, all in the browser. Tuning is instant and encode-free: the file is decoded with the Web Audio API and played through a GainNode whose value tracks the slider (gain = 10^(dB/20)), with an AnalyserNode driving a live clipping meter when the post-gain peak exceeds 0 dBFS. Export uses a self-hosted single-threaded ffmpeg.wasm engine (bundled core, no CDN): a manual boost applies -af volume=<N>dB (optionally with an alimiter true-peak guard), and normalize runs a true two-pass EBU R128 loudnorm — pass one measures integrated loudness, true peak and LRA, pass two applies a linear loudnorm to a selectable target (-14, -16, -19 or -23 LUFS). Output preserves the source format or can be MP3/WAV/OGG/M4A.
- Runs client-side — the audio is never uploaded
- Self-hosted ffmpeg core (bundled) — no CDN
- Instant GainNode preview with live clipping meter
- True 2-pass EBU R128 loudnorm (-14/-16/-19/-23 LUFS)
- True-peak limiter to prevent clipping
- Preserves source format or MP3/WAV/OGG/M4A
