Live Captions: Schedule Live Captions for an RTMP Stream

Once the Live Captioning module has been activated within 3Play Media, follow the steps below to schedule captions for an event using our RTMP workflow.

NOTE:  events default to US-Eastern time unless a new timezone has been configured at the user level and configured for users outside of the US-Eastern time zone.


Navigate to the Live Captioning page

Click into the Live Captioning module within your 3Play Media project and select RTMP as your platform option.


Select Service Type

3Play provides both Live Professional Captions as well as Live Auto Captions. Select the service type for your event using the dropdown. 

Add Event Name

Add in a name for your event that will make it easy for you to find the event when searching for it after scheduling. 


Select Event Start Time

Click the calendar icon to choose the MM/DD/YYYY and HH:MM:SS of the event. The time will automatically be set to 5 minutes from the current time but can be manually edited within the field.

  • Please note: The live event must be scheduled at least 5 minutes in the future and it is editable up until 5 minutes prior to the scheduled start time. 3Play will initiate a service to listen for your stream at this time. Do not attempt to stream to 3Play before the event start time, as the stream connection will fail.



Enter an Estimated Event Duration

An Estimated event duration is an estimate for the maximum amount of time that your event will last for. 3Play will be ready to provide you with captions through the entire duration that you provide to us using this information. 



Enter a Pre-Event Start Time


Different from your event start time, the pre-event start time will tell us how many minutes before your event you'd like to start sending your stream to us. This is before your event start time, and will allow us to listen to your stream before your actual event start time. This is useful if you may start earlier than scheduled. 


Streaming to 3Play from your encoder 

To allow 3Play to receive your stream and create captions, you will stream to 3Play's caption service from your encoder. As a default, 3Play will provide you with a stream target (transcoder). The RTMP URL address and Key to the stream target are provided on the confirmation page of this workflow; you'll enter this information into your encoder stream settings in preparation for the event.

  • You may also elect to use a Reserved Stream Target, please see this support document for additional information. If you do not have a reserved stream target, please set this option to "Use single-use transcoder". 

Streaming quality & bandwidth recommendation: 3Play recommends a stream >2mbps. 



Caption Delivery

Captions may be delivered to a captions embed, which is a code snippet (iFrame or Javascript) that can be added to a webpage (this requires access to the code through which the embed can be added). The following steps outline utilization of the captions embed.

3Play will also deliver captions to a second screen webpage, additional information on this captioning delivery method is available in this support document.


Note: With exception of a reserved embed or external web page, your caption link and embed code will be unique to each event. 

File Storage Location

Choose a folder within your 3Play Media account to send your finished live transcript to after your event is over. 



Improve Caption Accuracy 

Provide us with some additional information about your event to help our captioners and system caption your audio as accurately as possible. 


Select an Event Type

Tell us more about what captioner may be best for your event by selecting an accurate event type for us to categorize your event under. 



Provide an Event Description (optional)

Tell us more about your event with details to help our captioner research anything that they may need prior to your event starting. 


Provide a list of Speaker Names (optional) 

Provide us with a list of properly spelled speaker names for our captioners to use when captioning your event ( Live professional captioning ). 


Provide a Wordlist (optional)  

To improve accuracy of automated captions for a scheduled Live Captioning event, add a Wordlist of the proper nouns, terms, and phrases unique to your organization that may be commonly used during the event. 

Click to learn more information regarding Wordlists for Live Captioning Events


Set your Profanity Filter (optional)

Tell us how you'd like profanity in your event to be filtered, if at all. 


Advanced Settings

Set a Maximum  Captioning Delay 

Drag the dial button to the right of the screen to increase the Maximum Captioning Delay and to the left of the screen to decrease the Maximum Captioning Delay in milliseconds. This sets a delay between the stream we receive and the captions we output. The more the delay, the more accurate the output.

Please note: Do not delay the stream within the hosting platform and/or encoding software/hardware.


Set Constraints on your Event

Set your Stream Reconnection Wait Time

If your live stream disconnects during the event, this is how long we will wait before we disconnect from delivering captions. After this time has passed, you will no longer be able to connect to this event.


Set a Maximum Event Duration

Enter the duration in minutes of the live event to be live captioned. 

Note that this feature will determine the maximum length of the event and also act as a failsafe in case the streams are not manually stopped at the end of the live event.





Select a Captioning Overtime Option

Tell us how you'd like us to handle your event if you go past your estimated maximum event duration, until we hit your actual Max event duration. 


Enter Support Contact Information

Please enter contact information for your event host or the person streaming your event to us in the event that 3Play Technical support needs to get in touch.


Click Schedule Captioning

Click "Schedule captioning" on the right-hand side of the page to schedule your event once you have provided all of the necessary information. 


Copy Input RTMP URL & Key from the Confirmation Page

3Play will provide you with an Input RTMP URL & Key on the confirmation page. Enter this information into your encoder to stream to us when your event starts.  You can find this information under the event details on the lower right-hand side of the page for your event. If you cannot find this information after scheduling your event, you can find it by clicking "Live Captioning" in the upper portion of the page, clicking on the name of your event under upcoming events, and scrolling down to find the information on the lower right hand side of the page. 


Note: With the exception of a reserved stream target, your RTMP URL and Stream Key will be unique for each event. 

  • If you are running multiple RTMP events, you will need to ensure that you save the information for each event to enter into your transcoder before each event stream. 




Copy Embed Code

Once scheduled, the 3Play Live Captioning embed code will be immediately available and then can be added to your live event page. 

Copy the iFrame embed code under Live Captioning Details to paste onto your webpage. While a JavaScript embed is available the iFrame is the preferred embed code for most uses. The Javascript embed allows for advanced customization.


Please note: This embed code only contains the text/captions and not the video.

Click for information on how to customize the Captions Embed


Once the Live Captioning event has been scheduled, event settings can be edited up to 5 minutes prior to the Event Start Time that was selected in step 2.

Click for information on how to edit the live caption's event settings for a scheduled event



Additional Options Upon Completion of the Live Event

Manage and Upgrade Live Captioning Files

Edit a Live Captioning File





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