SRT to Speech API

Pricing

10 credits per 1,000 characters

The cost is calculated based on the total character count of all text in the SRT file.

Overview

The SRT to Speech API converts SRT subtitle files into synchronized speech audio. This endpoint merges the generated audio with the original video or creates standalone audio files with timing matched to the subtitle timestamps.

Endpoint

URL: POST https://api.revidapi.com/paid/srt-to-speech/merge
Method: POST

Request

Headers

x-api-key: Required. Your API key for authentication.
Content-Type: Required. Must be application/json.

Body Parameters

Required Parameters

Parameter	Type	Description
`srt_url`	string (URI)	URL of the SRT subtitle file
`video_url`	string (URI)	URL of the video file to merge with (optional for audio-only output)

Optional Parameters

Parameter	Type	Description
`engine`	string	TTS engine to use: `edge`, `capcut`, `google`. Default: `edge`
`voice_id`	integer	Voice ID for the selected engine
`voice`	string	Voice name (alternative to voice_id)
`speed`	number	Speech speed multiplier (0.5 to 2.0). Default: `1.0`
`pitch`	number	Voice pitch adjustment (-20 to 20). Default: `0`
`replace_audio`	boolean	If true, replaces original audio. If false, mixes with original. Default: `false`
`output_format`	string	Output format: `mp4`, `mp3`, `wav`. Default: `mp4`
`webhook_url`	string (URI)	URL to receive the result when processing is complete
`id`	string	Custom identifier for tracking the request

Example Request

{
  "srt_url": "https://example.com/subtitles.srt",
  "video_url": "https://example.com/video.mp4",
  "engine": "edge",
  "voice_id": 1001,
  "speed": 1.0,
  "replace_audio": false,
  "output_format": "mp4",
  "webhook_url": "https://example.com/webhook",
  "id": "srt-tts-request-123"
}

curl -X POST "https://api.revidapi.com/paid/srt-to-speech/merge" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "srt_url": "https://example.com/subtitles.srt",
    "video_url": "https://example.com/video.mp4",
    "engine": "edge",
    "voice_id": 1001,
    "speed": 1.0,
    "replace_audio": false,
    "webhook_url": "https://example.com/webhook",
    "id": "srt-tts-request-123"
  }'

Response

Immediate Response (202 Accepted)

When a webhook URL is provided, the API returns an immediate acknowledgment with a task_id:

{
  "code": 202,
  "id": "srt-tts-request-123",
  "task_id": "550e8400-e29b-41d4-a716-446655440000",
  "message": "processing"
}

Success Response (via Webhook or Direct)

{
  "code": 200,
  "id": "srt-tts-request-123",
  "task_id": "550e8400-e29b-41d4-a716-446655440000",
  "response": {
    "output_url": "https://storage.example.com/video/output.mp4",
    "duration": 120.5,
    "total_characters": 5432
  },
  "message": "success"
}

Error Responses

Invalid Request (400)

{
  "code": 400,
  "id": "srt-tts-request-123",
  "message": "Invalid request: 'srt_url' is a required property"
}

Authentication Error (401)

{
  "code": 401,
  "message": "Invalid API key"
}

Workflow Recommendation

For asynchronous processing:

Create Task: Send POST request to create the task
Wait: Add a wait node (30-45 seconds) to allow server processing time
Check Status: Use GET endpoint to check task status: GET https://tts.revidapi.com/api/get/{task_id}
Retrieve Result: Once status is "completed", retrieve the output URL from the response

Usage Notes

Character Counting: Credits are calculated based on the total character count of all subtitle text in the SRT file.
SRT Format: The SRT file must be in standard SRT format with proper timestamps.
Audio Synchronization: The generated speech is synchronized with the subtitle timestamps.
Webhook Processing: When a webhook_url is provided, the request is processed asynchronously.
Output Format: Choose the appropriate output format based on your needs (mp4 for video, mp3/wav for audio-only).

Common Issues

Invalid SRT Format: Ensure the SRT file is properly formatted with valid timestamps
URL Accessibility: Both srt_url and video_url must be publicly accessible
Processing Time: Large files with many subtitles may take longer to process

Best Practices

Use Webhooks: Always use webhooks for better reliability
Unique IDs: Provide unique id values for tracking
Test SRT Files: Validate SRT file format before submission
Voice Selection: Choose voices that match the language and tone of your content