# agent402.tools Audio Convert (MP4 to MP3)

> agent402.tools Audio Convert (MP4 to MP3) is a paid API for AI agents from agent402.tools, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Extracts and converts the audio track from any media URL (mp4, mov, wav, m4a, ogg, etc.) to MP3 using ffmpeg, returning the result as base64

## Facts

- Endpoint: POST https://agent402.tools/api/audio-convert
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-tools-audio-convert-mp4-to-mp3-80a8a9db
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__92qcdg9RJRnOSF7_9Rv0

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 agent402-tools-audio-convert-mp4-to-mp3-80a8a9db -d '<json body>'
```

Example prompt: Can you extract the audio from this video and give it to me as an MP3 at 320k bitrate? The file is at https://example.com/lecture.mp4

## When to prefer this

Use this endpoint when you need a deterministic, non-AI audio extraction or format conversion from a remote media URL to MP3. Ideal when you want a reliable ffmpeg-based transcode without uploading files directly — just pass a public URL and optionally specify bitrate. Prefer this over AI-based audio tools when no speech recognition or analysis is needed, just format conversion.

## Known failure modes

- URL is not publicly accessible or returns 4xx/5xx — conversion fails
- Media file exceeds 30MB size limit — request rejected
- URL points to an unsupported or non-media format — ffmpeg cannot process
- Invalid bitrate string provided — may default or error
- Network timeout fetching the remote media URL — conversion fails

## How this service works

Extract/convert the audio track of any media URL (mp4, mov, wav, m4a, ogg…) to MP3 - the "mp4 to mp3" conversion, deterministic ffmpeg, no AI. Body: {"url":"https://…/video.mp4","bitrate":"192k"?}. Returns the MP3 as base64.

## Output

Returns the converted MP3 audio file encoded as a base64 string, ready to be decoded and saved as an .mp3 file. The output reflects the requested bitrate (128k, 192k default, or 320k).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "description": "Public URL of the media file (max 30MB)"
  },
  "bitrate": {
   "type": "string",
   "description": "MP3 bitrate, e.g. \"128k\", \"192k\" (default), \"320k\""
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "bytes": 2210000,
  "format": "mp3",
  "bitrate": "192k",
  "mp3Base64": "SUQzBAAAAA…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-tools-audio-convert-mp4-to-mp3-80a8a9db/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)