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Media

Video Subtitle Add

Add hardcoded subtitles to videos using SRT, ASS, or VTT subtitle files with customizable font styling

file· File resultOpen tool

Quick start

Call this tool from your code in three languages.

cURL
# 1) Request a presigned URL → returns { uploadUrl, storageKey }
curl -X POST 'https://api.elysiatools.com/api/upload/presign/video-subtitle-add' \
  -H 'Content-Type: application/json' \
  -d '{"filename":"videoFile.ext","contentType":"application/octet-stream","size":12345}'
curl -X POST 'https://api.elysiatools.com/api/upload/presign/video-subtitle-add' \
  -H 'Content-Type: application/json' \
  -d '{"filename":"subtitleFile.ext","contentType":"application/octet-stream","size":12345}'

# 2) PUT the file bytes directly to the presigned uploadUrl
curl -X PUT '<presigned uploadUrl>' \
  --data-binary @/path/to/file.ext

# 3) Call the tool, passing the returned storageKey for each file field
curl -X POST 'https://api.elysiatools.com/en/api/tools/video-subtitle-add' \
  -F 'videoFile=uploads/2026/01/01/your-tool-1700000000000-abc123.ext' \
  -F 'subtitleFile=uploads/2026/01/01/your-tool-1700000000000-abc123.ext' \
  -F 'fontSize=24' \
  -F 'fontName=Arial' \
  -F 'fontColor=#FFFFFF' \
  -F 'bottomAlignment=true' \
  -F 'marginBottom=20' \
  -F 'outputFormat=mp4'

© 2026 Elysia Tools. Developer documentation.

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API reference

Send a POST request with your inputs as JSON. File parameters require a separate upload first.

Endpoint

HTTP
POST https://api.elysiatools.com/en/api/tools/video-subtitle-add

Parameters

NameTypeRequiredDescription
videoFilefileupload requiredYes—
subtitleFilefileupload requiredYes—
fontSizerangeNoFont size for subtitles (8-72 pixels, ignored for ASS/SSA files)
fontNametextNoFont family name (ignored for ASS/SSA files with embedded fonts)
fontColorcolorNoFont color in hex format (ignored for ASS/SSA files)
bottomAlignmentcheckboxNoAlign subtitles to bottom of screen (uncheck for top alignment)
marginBottomrangeNoDistance from bottom edge (0-200 pixels)
outputFormatselectNo—
File-type parameters must be uploaded first via POST /upload/video-subtitle-add, then the returned filePath is passed to the corresponding file field.

Response format

File result

JSON
{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}

MCP integration

Add this tool to your Model Context Protocol server so AI agents can list and call it.

Server configuration

Add this block to your MCP client configuration:

mcp.json
{
  "mcpServers": {
    "elysiatools-video-subtitle-add": {
      "name": "video-subtitle-add",
      "description": "Add hardcoded subtitles to videos using SRT, ASS, or VTT subtitle files with customizable font styling",
      "baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=video-subtitle-add",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

List available tools

After connecting to the SSE endpoint, list the exposed tools:

tools/list
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

Call this tool

Invoke the tool by its id, passing arguments built from its parameters:

tools/call
{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "video-subtitle-add",
    "arguments": {
  "videoFile": "https://example.com/file.ext",
  "subtitleFile": "https://example.com/file.ext",
  "fontSize": 24,
  "fontName": "Arial",
  "fontColor": "#FFFFFF",
  "bottomAlignment": true,
  "marginBottom": 20,
  "outputFormat": "mp4"
}
  }
}
Chain multiple tools in one session with a comma-separated toolId list, e.g. /mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp (max 20).
File parameters accept a public file URL only (https://…). Local paths, data: URIs, and Base64 strings are not supported.

Questions or issues? Contact [email protected]

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