Audio normalize (EBU R128)

Loudness-normalize any audio/video URL to a target LUFS with ffmpeg's loudnorm (EBU R128) and return MP3 - consistent levels for podcasts, clips, and TTS output. Body: {"url":"https://…/audio.wav","targetLufs":-16?}.

Input

Example output

{
  "format": "mp3",
  "targetLufs": -16,
  "truePeakDb": -1.5,
  "bytes": 2210000,
  "mp3Base64": "SUQzBAAAAA…"
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/audio-normalize \
  -H "Content-Type: application/json" \
  -d '{"url":"https://upload.wikimedia.org/wikipedia/commons/c/c8/Example.ogg"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/audio-normalize", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "url": "https://upload.wikimedia.org/wikipedia/commons/c/c8/Example.ogg"
  }),
});

Part of these workflows

This tool is one step in a curated multi-tool workflow - agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• Uploaded-media normalize - The 'user uploaded a thing, normalize it before storing' workflow. Probe the file (image or audio/video) with media-info, decode any embedded barcodes/QRs, resize and thumbnail the image, convert it to a web-friendly format, and normalize audio loudness to broadcast standard. Six tools, one canonical normalize-on-upload pipeline that turns arbitrary user uploads into predictable storage artifacts.

Related tools