Subtitle Generator and API

Automatically generate subtitles from an input audio or video file using Open AI Whisper.

🚀 Try it instantly with Eyevinn Open Source Cloud

Skip the setup and start generating subtitles immediately! The Subtitle Generator is available as a fully managed service in Eyevinn Open Source Cloud.

Why choose the managed service?

• 🎯 Zero setup required - No need to install FFmpeg, manage OpenAI API keys, or configure AWS
• ⚡ Production-ready infrastructure - Scalable, reliable subtitle generation at enterprise scale
• 🛠️ Professional support - Real-time support in our Slack workspace
• 📊 Multiple formats - Generate SRT, VTT, and other subtitle formats
• 🌍 Multi-language support - Process content in multiple languages with OpenAI Whisper
• 🔒 Secure processing - Your content is processed securely with industry-standard practices

Perfect for video streaming platforms, broadcast content, accessibility improvements, and multilingual content creation. Check pricing and get started in minutes.

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Prefer to self-host? Continue reading to set up your own instance.

Features

• Transcribe and translate audio to generate subtitle files (translation limited to English).
• Split large files into audio chunks to handle 25 MB file size limit and keeps track of timing information.
• Combines all segments with correct timecodes.
• Supports different output formats (VTT, SRT, JSON, text)
• Maintain context and improve continuity between chunks by giving Whisper some context about what was transcribed in the previous chunk.
• Produce more professional-looking subtitles that are easier to read and follow industry standards for broadcast and streaming platforms:
  • Characters per line limit for better readability
  • Appropriate duration based on text length
  • Natural line breaks at logical points
  • Minimum duration to ensure readability
  • Maximum duration to maintain attention

Setup

Requirements

The following environment variables can be set:

OPENAI_API_KEY=<your-openapi-api-key>
AWS_REGION=<your-aws-region> (optional can also be provided in payload)
AWS_ACCESS_KEY_ID=<your-aws-access-key-id> (optional, only needed when uploading to S3)
AWS_SECRET_ACCESS_KEY=<your-aws-secret-access-key> (optional, only needed when uploading to S3)
AWS_S3_ENDPOINT=<aws-s3-endpoint> (optional)

Using an .env file is supported. Just rename .env.example to .env and insert your values.

FFmpeg

FFmpeg is required to convert the input file/url to a format that Open AI Whisper can process. You can download it from here.

Installation / Usage

Starting the service is as simple as running:

npm install
npm start

A docker image and docker-compose are also available:

docker-compose up --build -d

The transcribe service is now up and running and available on port 8000.

Endpoints

Available endpoints are:

Endpoint	Method	Description
/	GET	Heartbeat endpoint of service
/transcribe	POST	Create a new transcribe job. Provide url in body
/transcribe/s3	POST	Create a new transcribe job and upload result to s3

Example requests

To start a new transcribe job send a POST request to the /transcribe endpoint with :

{
  "url": "https://example.net/vod-audio_en=128000.aac",
  "language": "en", // ISO 639-1 language code (https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes) (optional)
  "format": "vtt" // Supported formats: srt or vtt (default)
}

The response will look like this where result is the WEBVTT file as a string:

{
  "workerId": "BFabbcCi3IYuWOj6LfsgK",
  "result": "WEBVTT\n\n00:00:00.000 --> 00:00:04.180\nor into transcoding I mean, I could probably add just the keyframe in the start and just\n\n00:00:04.180 --> 00:00:06.920\nskip I-frames and the rest of that.\n\n"
}

Formatted output:

WEBVTT

00:00:00.000 --> 00:00:01.940
So into transcoding, I mean, I could

00:00:01.940 --> 00:00:03.700
probably add just a keyframe in the start

00:00:03.700 --> 00:00:06.700
and then just skip iFrames in the rest of the scenes.

Contributing

See contributing

Support

Join our community on Slack where you can post any questions regarding any of our open source projects. Eyevinn's consulting business can also offer you:

• Further development of this component
• Customization and integration of this component into your platform
• Support and maintenance agreement

Contact sales@eyevinn.se if you are interested.

About Eyevinn Technology

Eyevinn Technology is an independent consultant firm specialized in video and streaming. Independent in a way that we are not commercially tied to any platform or technology vendor. As our way to innovate and push the industry forward we develop proof-of-concepts and tools. The things we learn and the code we write we share with the industry in blogs and by open sourcing the code we have written.

Want to know more about Eyevinn and how it is to work here. Contact us at work@eyevinn.se!