# Relaystation Media Concat

> Relaystation Media Concat is a paid API for AI agents from api.relaystation.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Joins 2–10 video or audio clips end-to-end via stream-copy (no re-encode) at $0.0005/MB, billed by the megabyte with a 1¢ x402 minimum.

## Facts

- Endpoint: POST https://api.relaystation.ai/v1/media/concat
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/relaystation-media-concat-5dd20b83
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mcv8Yo2Q2m9gVVWZYMQpk

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 relaystation-media-concat-5dd20b83 -d '<json body>'
```

Example prompt: Stitch these 3 MP4 clips together into one file without re-encoding — clip1.mp4, clip2.mp4, and clip3.mp4 — and give me the merged video back.

## When to prefer this

Choose this endpoint when you need to join multiple video or audio clips together quickly and losslessly — it uses stream-copy so there is zero quality degradation and processing is very fast. Prefer it over re-encoding pipelines when the clips share the same codec and container. It is ideal for assembling pre-edited segments, podcast parts, or recorded clips into a final file without transcoding overhead. The per-MB pricing makes it economical for small-to-medium media files.

## Known failure modes

- Mismatched codecs or container formats between clips may cause stream-copy to fail or produce unplayable output
- Fewer than 2 or more than 10 clips provided results in a validation error
- Input clip URLs that are inaccessible or expired return a fetch/download error
- Total file size or clip count exceeding platform limits returns a size/limit error
- Insufficient USDC balance for the per-MB cost returns a payment failure

## How this service works

$0.0005/MB. Join 2–10 clips end-to-end by fast stream-copy — no quality loss, no re-encode. 1¢ x402 min; remainder auto-credits — relaystation.ai/penny

## Output

A single concatenated media file produced by lossless stream-copy, containing all input clips joined end-to-end in the specified order. No re-encoding occurs so the output retains the original codec and quality. The response includes the output file or a URL to download it, along with billing details based on total MB processed.

## 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": {
     "type": "object",
     "properties": {
      "ext": {
       "enum": [
        "mp4",
        "mov",
        "mkv",
        "mp3",
        "m4a",
        "aac",
        "wav",
        "ogg",
        "flac"
       ],
       "type": "string"
      },
      "files": {
       "type": "array",
       "items": {
        "type": "object",
        "description": "cputools input-source: { inline: <base64 ≤ 4 MiB> } or { inputKey: <scratch key ≤ 50 MB> }. The input container must sniff (ffprobe) to the live allowlist (operator-tunable cputools.media.input_formats): 3g2, 3gp, aac, asf, avi, flac, flv, gif, m4a, m4v, matroska, mj2, mov, mov,mp4,m4a,3gp,3g2,mj2, mp3, mp4, mpeg, mpegts, mpegvideo, ogg, wav, webm, wmv. An off-list input is a free 422 UNSUPPORTED_FORMAT."
       },
       "maxItems": 10,
       "minItems": 2
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/relaystation-media-concat-5dd20b83/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.relaystation.ai](https://www.zero.xyz/host/api.relaystation.ai/llms.txt)