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Shift subtitles | agent view

The same page content and links, with explicit tool capabilities. Tools marked with an API can run directly through HTTP. Other tools require the browser interface or are not connected yet.

Tool capabilities

{
  "id": "shift-subtitles",
  "category": "subtitle-tools",
  "built": true,
  "requirements": "Apply positive/negative offset; report negative timestamps and preserve cue order.",
  "implementation": {
    "fields": [
      {
        "key": "seconds",
        "label": "Shift seconds (negative = earlier)",
        "value": 0,
        "type": "number"
      }
    ],
    "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": "Your text",
      "placeholder": "Hello world!",
      "help": "Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/shift-subtitles/run",
  "api": {
    "id": "shift-subtitles",
    "name": "Shift subtitles",
    "category": "subtitle-tools",
    "description": "Apply positive/negative offset.",
    "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/shift-subtitles/",
    "method": "POST",
    "endpoint": "/api/v1/tools/shift-subtitles/run",
    "schema_url": "/api/v1/tools/shift-subtitles",
    "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": {
            "seconds": {
              "type": "number",
              "description": "Shift seconds (negative = earlier)",
              "default": 0.0
            }
          }
        }
      }
    },
    "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

Apply positive/negative offset.

Useful next steps

SRT to VTT

Convert timestamp punctuation and cue structure.

VTT to SRT

Warn when VTT styling/position metadata is lost.

Subtitles to text

Remove timecodes and optionally repeated captions.

How to use Shift subtitles

  1. Enter your text 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 shift subtitles

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: SRT to VTT, VTT to SRT, Subtitles to text.