# Rengi Forge Audio Loop Creator

> Rengi Forge Audio Loop Creator is a paid API for AI agents from rengi.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-10-22).

Converts a music track or ambient audio into a seamless loop by cutting at zero crossings and applying an equal-power crossfade from the end back into the start, returning the looped file, a 3x preview, and loop point positions in samples.

## Facts

- Endpoint: POST https://rengi.dev/v1/audio-tools/loop?utm_source=zero.xyz
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rengi-forge-audio-loop-creator-e93c9175
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IRgkMSTg3_u4fmN1TlJEA

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 rengi-forge-audio-loop-creator-e93c9175 -d '<json body>'
```

Example prompt: Take this background music file at audioUrl https://example.com/music.mp3, loop the section from 2 seconds to 45 seconds with a 200ms crossfade, and give me back an ogg file that loops perfectly with no click.

## When to prefer this

Use this endpoint when you need a technically clean, click-free looping audio file — especially for game background music, ambient web audio, or any scenario where the loop must repeat indefinitely without an audible seam. It is specifically designed for zero-crossing cuts and equal-power crossfades, which is superior to naive sample-level cuts. Prefer it over generic audio editors when you need automated loop-point detection and a ready-to-use preview in a single API call.

## Known failure modes

- Audio file cannot be decoded (unsupported codec or corrupt data) — returns an error with format details
- crossfadeMs value exceeds the duration of the selected loop region — returns a validation error
- Neither audio nor audioUrl provided — returns a missing-input error
- Audio URL is unreachable or returns a non-audio response — returns a fetch error
- Audio is too short for the requested start/end window — returns an out-of-bounds error

## How this service works

Audio tools: Turn music or ambience into a seamless loop: cuts at zero crossings and crossfades the end into the start with an equal-power curve. Returns the loop, a 3x preview and loop points in samples. Full schema: https://rengi.dev/v1/audio-tools/schema

## Output

Returns the processed looped audio file in the requested format (ogg, wav, or mp3), a 3x-length preview file demonstrating the loop transition, and the loop start and end points expressed in samples so they can be embedded in an audio engine or DAW.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "mono": {
   "type": "boolean",
   "default": false
  },
  "audio": {
   "type": "string",
   "description": "Audio file as base64 (wav, mp3, ogg, flac, m4a)."
  },
  "endSec": {
   "type": "number",
   "minimum": 0
  },
  "format": {
   "enum": [
    "ogg",
    "wav",
    "mp3"
   ],
   "type": "string",
   "default": "ogg"
  },
  "audioUrl": {
   "type": "string",
   "format": "uri",
   "description": "Audio file URL."
  },
  "startSec": {
   "type": "number",
   "minimum": 0
  },
  "crossfadeMs": {
   "type": "number",
   "default": 120,
   "maximum": 2000,
   "minimum": 5
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rengi-forge-audio-loop-creator-e93c9175/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from rengi.dev](https://www.zero.xyz/host/rengi.dev/llms.txt)