# SRT to VTT

- Human page: https://happytails.ai/en/subtitle-tools/srt-to-vtt/
- Markdown: https://happytails.ai/en/subtitle-tools/srt-to-vtt.md
- Structured JSON: https://happytails.ai/agents/en/subtitle-tools/srt-to-vtt/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `srt-to-vtt` |
| Category | subtitle-tools |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Automatic updates after valid input or file selection. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | /api/v1/tools/srt-to-vtt/run |
| Browser-agent interface | run_current_tool |

### Implementation notes

Paste editable subtitle text or use Open text file. Styling and cue layout metadata are normalized; review overlaps after editing.

### Inputs and settings

Text input: SRT subtitles.

Example or placeholder shown in the interface (not a validated fixture):

```text
1
00:00:01,000 --> 00:00:02,000
Hello world
```

Keep the numbered cues and timestamp lines. Results update as you type. Up to 1,000,000 characters.

No additional settings are declared for this tool.

### HTTP contract

API calls process supplied data on the server. The website origin is `https://happytails.ai`. Server API hosting is not connected on the public website yet. Use your local server origin to test these requests.

```http
POST https://happytails.ai/api/v1/tools/srt-to-vtt/run
Content-Type: application/json
```

[Detailed operation reference](https://happytails.ai/en/api/tools/srt-to-vtt.md) · [Shared API guide](https://happytails.ai/en/api.md)

#### Limits

| Limit | Value |
| --- | --- |
| request_bytes | 8388608 |
| input_characters | 1000000 |
| files_bytes | 5242880 |
| max_files | 0 |
| timeout_seconds | 12 |

#### Complete input schema

```json
{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "input": {
      "type": "string",
      "maxLength": 1000000,
      "default": "",
      "description": "Plain text input. File tools use files instead unless otherwise documented."
    },
    "options": {
      "type": "object",
      "additionalProperties": false,
      "properties": {}
    }
  }
}
```

#### Complete output schema

```json
{
  "type": "object",
  "required": [
    "tool",
    "result"
  ],
  "properties": {
    "tool": {
      "type": "string"
    },
    "result": {
      "type": "object",
      "required": [
        "text",
        "files"
      ],
      "properties": {
        "text": {
          "type": [
            "string",
            "null"
          ]
        },
        "data": {
          "description": "Parsed JSON when the textual result is JSON."
        },
        "name": {
          "type": "string"
        },
        "mime": {
          "type": "string"
        },
        "files": {
          "type": "array",
          "items": {
            "type": "object",
            "required": [
              "name",
              "mime",
              "bytes",
              "base64"
            ],
            "properties": {
              "name": {
                "type": "string"
              },
              "mime": {
                "type": "string"
              },
              "bytes": {
                "type": "integer"
              },
              "base64": {
                "type": "string",
                "contentEncoding": "base64"
              }
            }
          }
        }
      }
    }
  }
}
```

#### Error and retry handling

Failures return a non-200 status and `error.code` plus `error.message`. Correct invalid input before retrying; retry server-busy responses with bounded backoff. Returned files contain Base64 data, not persistent download URLs. Decode and inspect the output before treating conversion as successful. See the shared API guide for the complete status and timeout rules.

### Browser-agent workflow

1. Open the human page in a browser that supports WebMCP.
2. Discover the interface exposed by that page; use its actual schema.
3. Select files on the page first when the tool requires files.
4. Call `run_current_tool` with valid input and settings.
5. Inspect the returned result or error and the displayed output. Retrieve files from the displayed download links.

Calls do not automatically copy or download results. Browser permissions still apply. Interface availability alone is not proof of successful execution.

### Planning specification

Convert timestamp punctuation and cue structure; preserve supported text and validate timing.

This describes intended requirements. Use the implementation notes, interface schema and observed output to determine current support.

### Complete machine-readable capability record

```json
{
  "id": "srt-to-vtt",
  "category": "subtitle-tools",
  "built": true,
  "requirements": "Convert timestamp punctuation and cue structure; preserve supported text and validate timing.",
  "implementation": {
    "fields": [],
    "note": "Paste editable subtitle text or use Open text file. Styling and cue layout metadata are normalized; review overlaps after editing.",
    "experience": {
      "automatic": true,
      "single": false,
      "label": "SRT subtitles",
      "placeholder": "1\n00:00:01,000 --> 00:00:02,000\nHello world",
      "help": "Keep the numbered cues and timestamp lines. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/srt-to-vtt/run",
  "api": {
    "id": "srt-to-vtt",
    "name": "SRT to VTT",
    "category": "subtitle-tools",
    "description": "Convert timestamp punctuation and cue structure.",
    "notes": "Paste editable subtitle text or use Open text file. Styling and cue layout metadata are normalized; review overlaps after editing.",
    "human_path": "/en/subtitle-tools/srt-to-vtt/",
    "method": "POST",
    "endpoint": "/api/v1/tools/srt-to-vtt/run",
    "schema_url": "/api/v1/tools/srt-to-vtt",
    "input_schema": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "input": {
          "type": "string",
          "maxLength": 1000000,
          "default": "",
          "description": "Plain text input. File tools use files instead unless otherwise documented."
        },
        "options": {
          "type": "object",
          "additionalProperties": false,
          "properties": {}
        }
      }
    },
    "output_schema": {
      "type": "object",
      "required": [
        "tool",
        "result"
      ],
      "properties": {
        "tool": {
          "type": "string"
        },
        "result": {
          "type": "object",
          "required": [
            "text",
            "files"
          ],
          "properties": {
            "text": {
              "type": [
                "string",
                "null"
              ]
            },
            "data": {
              "description": "Parsed JSON when the textual result is JSON."
            },
            "name": {
              "type": "string"
            },
            "mime": {
              "type": "string"
            },
            "files": {
              "type": "array",
              "items": {
                "type": "object",
                "required": [
                  "name",
                  "mime",
                  "bytes",
                  "base64"
                ],
                "properties": {
                  "name": {
                    "type": "string"
                  },
                  "mime": {
                    "type": "string"
                  },
                  "bytes": {
                    "type": "integer"
                  },
                  "base64": {
                    "type": "string",
                    "contentEncoding": "base64"
                  }
                }
              }
            }
          }
        }
      }
    },
    "processing": "Server; same transformation code as browser tools",
    "limits": {
      "request_bytes": 8388608,
      "input_characters": 1000000,
      "files_bytes": 5242880,
      "max_files": 0,
      "timeout_seconds": 12
    }
  },
  "agent_processing": "Server; same transformation code as browser tools",
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}
```

## Page guide

Convert timestamp punctuation and cue structure.

## Useful next steps

- [VTT to SRT](https://happytails.ai/en/subtitle-tools/vtt-to-srt/): Warn when VTT styling/position metadata is lost. ([Markdown](https://happytails.ai/en/subtitle-tools/vtt-to-srt.md))

- [Shift subtitles](https://happytails.ai/en/subtitle-tools/shift-subtitles/): Apply positive/negative offset. ([Markdown](https://happytails.ai/en/subtitle-tools/shift-subtitles.md))

- [Subtitles to text](https://happytails.ai/en/subtitle-tools/subtitles-to-text/): Remove timecodes and optionally repeated captions. ([Markdown](https://happytails.ai/en/subtitle-tools/subtitles-to-text.md))

## How to use SRT to VTT

1. Enter srt subtitles in the input field.
2. The result updates as you type. Adjust the available settings if needed.
3. Review the result, then use Copy result or a download link when available.

## Working with srt to vtt

A subtitle file combines text with time ranges. Converting SRT to VTT changes its representation; shifting subtitles changes timing; translation changes the language. Generating subtitles from speech adds a transcription step before the captions can be reviewed.

## Common questions

### Does converting subtitle formats fix synchronization?

No. A format conversion generally retains the source timing. Constant offsets can be adjusted with a shift; drift across a recording may require timing alignment or manual correction.

### Why do translated subtitles need another review?

Translated text may be longer than the original even when its meaning is correct. Review line breaks and reading speed without assuming that the original cue duration suits every language.

Continue your workflow: [VTT to SRT](https://happytails.ai/en/subtitle-tools/vtt-to-srt/), [Shift subtitles](https://happytails.ai/en/subtitle-tools/shift-subtitles/), [Subtitles to text](https://happytails.ai/en/subtitle-tools/subtitles-to-text/).