Last updated: March 23, 2023

1. Real-time Captioning Overview

Real-time captioning support both open captions and closed captions(CC).

- Open captions
Captions are always displayed in the video and viewers cannot turn them off. Captions that can be used in the CameraFi Live app or broadcasting programs (OBS, Xsplit, etc.) that allow overlay input.

- Closed captions (CC)
Captions that viewers can turn on and off. We currently support OBS, YouTube, and Zoom. Depending on the platform you want to use, the information you need to enter in settings is different.

2. Create Captions

If you select [Real-Time Captioning] from ‘Get Started Now!’ at the top of the home screen or select [Real-Time Captioning] from Create next to your profile at the top right, the [Caption Settings] window will appear.

Real-time Captioning Create PC screen

3. Caption Settings

Settings are divided into 4 categories on the left: [General], [Input], [Open Captions], and [Closed Captions]. Below are descriptions of some settings that can be difficult to understand.

Caption Settings window PC screen

[Input] > [Input] > [Automatic sending] > [Auto Input Interval (ms)]
This feature automatically sends captions after a certain period of time after inputting them. It is to prevent the mistake of not sending inputted captions. 
- Default setting:  Deactivated
- Default setting when activated: 3000 ms,  can be changed in units of 1000 ms.

[Input] > [Input Settings] > [Minimum length sent by spacebar]
This function prevents subtitles from being displayed for too long on one screen. You can set the length to be automatically sent when you press the spacebar while typing continuously without stopping.
- Default setting: 80 characters, can be changed in increments of 10 characters

[Input] > [Speech-to-Text]
This feature automatically converts speech into text. Captions are output in characters of the detecting language.
(If you select English as the detecting language and speak Korean, captions with Korean pronunciation will be output in the English alphabet.)

[Input] > [Translation]
This feature automatically translates captions. [Language to be translated] means B language when translated from A to B.
The [Apply filtering to translated languages] checkbox is a setting that selects whether to apply filtering before or after translation when using the filtering function. By default, filtering is applied to the input language A, and if checked, filtering is applied to the translated language B.

[Input] > [Filtering]
This is a function to apply a filter to captions. If you set Before and After by text or regular expression, captions can be converted or eliminated.

[Open Captions] > [Text-to-Speech]
This function converts the entered text into speech. You need to activate the switch on the top right and select the language and voice to be synthesized.

[Cloased Captions]
You will need to select a platform to send subtitles to. When you activate the platform, you must enter the required input values to create it.
* Platforms will be added.

4. Using the Real-time Captioning

Currently, available real-time captioning services are listed in the table below.

Available Real-time Captioning services

1) Overlay (Open captions)

Captions entered on the CameraFi Studio web page are displayed on the broadcast screen through the overlay URL.
You can use it by pasting the [Open Caption Overlay URL] into the web source of the broadcasting program.

Here's how to add a web overlay on the CameraFi Live app.
a) Press the [Copy] button of the Open Caption Overlay URL to copy it.
b) In the CameraFi Live app, swipe right to left and select Web from the menu.
c) Tap + to add a web overlay. The overlay can be moved and resized when it is OFF.
d) Tap the overlay you will see the settings. Enter the copied URL.

CameraFi Live web overlay setting screen

e) When you turn it ON, the entered captions are displayed on the screen. The entered captions are displayed on top of the overlay, just like the preview of the output.

Example screen of CameraFi Live real-time captioning input

2) Add closed captions in YouTube

a) 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 Stream Settings PC screen 

b) Activate the YouTube platform under Closed Captions in Settings and enter the [Closed Caption URL].

CameraFi Studio Closed Captions setting PC screen 

3) Add closed captions in Zoom

a) 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 Meeting (Advanced) setting PC screen

b) 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

c) Activate the Zoom platform under Closed Captions in Settings and enter [API token].

CameraFi Studio Closed Captions setting PC screen 

4) Add closed captions in OBS Studio (for Twitch stream)

* OBS studio only supports English for the closed caption language.
a) Create a Twitch stream through OBS Studio.
b) 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

c) 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

d) 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.