# x402.agentutility.ai Audio Loudness Normalizer

> x402.agentutility.ai Audio Loudness Normalizer is a paid API for AI agents from x402.agentutility.ai, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-16).

Normalizes audio loudness to a target LUFS level (EBU R128) for podcast, YouTube, or streaming delivery, returning a hosted MP3 URL

## Facts

- Endpoint: POST https://x402.agentutility.ai/audio-loudnorm
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-agentutility-ai-audio-loudness-normalizer-2eb0df7e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jM2XvOkmfFb9ZpHYQaBUK

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-agentutility-ai-audio-loudness-normalizer-2eb0df7e -d '<json body>'
```

Example prompt: Can you normalize the loudness of this podcast episode — https://example.com/episode42.mp3 — to -16 LUFS with a true peak of -1.5, so it's ready for podcast distribution?

## When to prefer this

Choose this endpoint when you need a simple, pay-per-call API to normalize audio loudness to a specific LUFS target before publishing to podcasts, streaming platforms, or broadcast. It handles the full EBU R128 two-pass normalization pipeline and returns a ready-to-use hosted MP3, making it ideal for automated publishing workflows without managing your own ffmpeg infrastructure.

## Known failure modes

- Audio file longer than 60 minutes is rejected
- Invalid or inaccessible audio_url returns an error
- target_lufs out of range (-30 to -10) returns a validation error
- true_peak out of range (-9 to 0) returns a validation error
- Network timeout if source audio file is very large or slow to download
- Unsupported audio format may cause processing failure

## How this service works

Normalize audio loudness to a target LUFS level for podcasts, YouTube, and Spotify delivery. Send an audio_url plus an optional target_lufs (defaults to -16) and true_peak, and it probes duration, runs two-pass EBU R128 loudness normalization, and returns a hosted MP3 URL with the applied target and duration in seconds. Common presets: -23 for broadcast, -16 for podcasts, -14 for streaming platforms. Use it as a loudness normalizer, LUFS correction API, or audio mastering step before publishing.

## Output

Returns a JSON object with a hosted MP3 URL pointing to the loudness-normalized audio file, the applied target_lufs value used, and the duration of the audio in seconds.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "required": [
      "audio_url"
     ],
     "properties": {
      "audio_url": {
       "type": "string",
       "description": "URL of the audio file to normalize. Rejected if longer than 60 minutes."
      },
      "true_peak": {
       "type": "number",
       "description": "Default -1.5. Range -9 to 0."
      },
      "target_lufs": {
       "type": "number",
       "description": "Default -16. Range -30 to -10."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "audio_url": {
       "type": "string"
      },
      "target_lufs": {
       "type": "integer"
      },
      "duration_seconds": {
       "type": "integer"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "audio_url": "https://...mp3",
  "target_lufs": -16,
  "duration_seconds": 120
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-agentutility-ai-audio-loudness-normalizer-2eb0df7e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentutility.ai](https://www.zero.xyz/host/x402.agentutility.ai/llms.txt)