Setting Up Output Captions in a Sidecar Format (SCC, SMI, SRT, TTML, WebVTT) - AWS Elemental Server

This is version 2.15 of the AWS Elemental Server documentation. This is the latest version. For prior versions, see the Previous Versions section of AWS Elemental Conductor File and AWS Elemental Server Documentation.

Setting Up Output Captions in a Sidecar Format (SCC, SMI, SRT, TTML, WebVTT)

To set up sidecar captions in an output, you create separate, captions-only streams. Each stream corresponds to one captions track. You set up a separate output to associate with each stream. On the AWS Elemental Server web interface, your outputs are structured as shown in the following diagram.

     There are three outputs, one for audio and video together, and one for each output
      captions track.

To set up sidecar format captions in an output

  1. On the Create New Job page, find the very light gray Output Groups section at the bottom of the job.

  2. Choose the output group tab that contains the output that you want your sidecar captions to go with.

    If you have not already set up the video and audio for the outputs in this output group, set them up first, before you set up the captions.

  3. Create a stream for the first captions track that you want to include.

    1. Find the Streams section on the tab for your output group below the Outputs section.

    2. In the upper right corner of the Streams section, choose the arrow beside the Add Stream button. This brings up a drop-down menu.


      Do not choose the Add Stream button itself.

    3. From the drop-down menu, choose Add Captions Only Stream.

    4. Specify values for the settings in the stream as described in the table following this procedure.

  4. Create a new output and associate your captions-only stream with it.


    AWS Elemental Server associates this output with your audio and video output because they are in the same output group.

    1. Find the dark gray New Output section on your output group tab, just above the Outputs section.

    2. For Stream, choose the captions-only stream you created earlier in this procedure.

    3. Choose the orange Add Output button.

  5. Create an additional captions-only stream and output for each additional captions track you want to include. Associate each stream with an output.




Caption Source


Select the caption selector you created when specifying the input captions. For more information see Creating Input Captions Selectors)

Destination Type


Select the caption type. This type must be valid for your output type as per the relevant Supported Captions table.

Framerate If the Destination Type is SCC.

Complete this field to ensure that the captions and the video are synchronized in the output.

Specify a framerate that matches the framerate of the associated video.

  • If the video framerate is 23.97 or 24, choose the corresponding option

  • If the video framerate is 29.97, choose 29.97 dropframe only if the video has the Video Insertion and Drop Frame Timecode both checked; otherwise, choose 29.97 non-dropframe.


If Destination Type is TTML.

And if:

  • The source caption type is TTML, SMPTE-TT, or CCF-TT.

  • And the output is an Archive output.

Complete as follows:

  • Check this box if you want the style (font, position, and so on) of the input captions to be copied.

  • Leave unchecked if you want a simplified caption style. Some client players work best with a simplified caption style.

(For other combinations of source caption types and output caption type, the output is always simplified.)

Font style fields

If the Destination Type is Burn-in.

See Font Styles for Burn-in.



Complete if desired. This information may be useful to or required by a downstream system.



Complete if desired. This information may be useful to or required by a downstream system.