CameraFi Studio

Real-time Captioning User Guide

Last updated: November 29, 2022

1. Create Real-time Captioning and Settings

Select [Real-time Captioning] on the left menu, then the subtitle creation and list page will appear. When you first sign in, the list has neither created captions nor past captions. If you click the [CREATE] button on the upper right, the following window appears. You must enter the title to create. If you press the down arrow, detailed settings will appear.

Create Real-time captioning

Various settings are supported. Here's a brief explanation of some of the settings that can be difficult to understand.

  • [INPUT] > [Auto input interval(ms)] is a function that is automatically transmitted after 3 seconds when the input is not transmitted. Interval time can be changed in units of 1000 ms.

  • [INPUT] > [Least length send by spacebar] is a function that is automatically sent when you press the space bar when you enter more than 80 characters without a space. This function helps when you do not transmit a long sentence and continue typing. Settings can be changed in units of 10 characters.

  • [INPUT] > [Speech to text(STT)] is a function that converts voice to text, and you must select a language to be detected.

  • [INPUT] > [Teanslate] is an automatic translation function, and [Translated language] means B language when translated from A to B. 

  • [OPEN CAPTION] > [Text to speech(TTS)] is a function that converts text to speech, and you must select the language and voice to be synthesized.

  • [CLOSED CAPTION] requires you to select the platform you want to transfer the captions. When you activate the platform, you must enter the required input values to create it.
    * Platforms will be added through future updates.

  • [FILTERING] is a function to apply a filter to captions. Words can be converted or eliminated.

2. Using the captioning service

Currently, supported captioning services are listed in the table below.

Supported Real-time Captioning services

1) Add open captions using web overlays
  • When subtitles are entered in the [Real-time input] box, subtitles are provided through the overlay URL. You can use the service in the open caption method by using the overlay function of the streaming software that broadcasts the captioning provided by the overlay URL.

2) Add closed captions in Youtube
  • After creating YouTube [Live Streaming], enable [Closed captions]. Copy the [Captions ingestion URL] provided when [Caption source] is selected as [Post caption to URL].
    YouTube Steam Settings
  • Activate the YouTube platform under Closed Captions in Settings and enter the [Closed Caption URL].

3) Add closing captions in Zoom
  • After signing in to Zoom, you can use [Show Captions] in meetings by enabling [Manual captions] in the [In Meeting (Advanced)] section at the bottom of My Account > PERSONAL > Settings > Meeting.
    Zoom In Meetings (Advanced) Settings
  • After completing the above settings, start a meeting and select [Show Captions] > [Set up manual captioner] > [Copy the API token].
    Zoom Copy the API token
  • Activate the Zoom platform under Closed Captions in Settings and enter [API token].

4) Add closing captions in OBS Studio (for Twitch stream)
  • Create a Twitch stream through OBS Studio.

  • In OBS Studio, go to Tools > obs-websocket Settings.
    • Check Enable WebSocket server
    • Specify Server Port
    • Check Enable Authentication
      (You can check the password by clicking the Show Connect Info button.)
      obs-websocket Settings

  • Configure port forwarding to allow access to the server port number.
    • Access and follow the instructions after registering as a member. (Installation and account connection)
    • After the installation and account connection, open a terminal and enter ngork tcp [server port] as a command.
      (If the server port in the photo above is 4455, enter ngrok tcp 4455.)
    • Then the following screen appears. Check the values in the underlined part. Port forwarding
  • Activate the OBS platform under Closed Captions in Settings and enter the values obtained through the port forwarding and the server password.
    • Server IP address:
    • Server Port: 13440
    • Server Password: The password that you checked from Show Connect Info.