Closed Captioning for Broadcast using ProMedia Carbon

With many broadcast stations and cable distribution networks switching from tape to file-based delivery, choosing an encoder that will create the right delivery format with encoded closed captions is critical. This tutorial describes how to add CEA-608/708 closed captions to video using Harmonic's ProMedia Carbon and an SCC output file from CaptionSync.

Text Tutorial

Many television and cable networks are phasing out tape submission in favor of file-based content delivery. CaptionSync can provide captions in several output formats commonly used by broadcast producers, such as the Sonic Scenarist (SCC) format, which can then be used to encode closed captions into the final video files delivered to your station or distribution network. Harmonic’s ProMedia Carbon, also known as Carbon Coder or Rhozet, is a powerful and flexible encoder that offers a wide range of codecs and presets suitable for broadcast and cable distribution. This tutorial walks you through the steps required to insert broadcast captions into a video using ProMedia Carbon and an SCC file from CaptionSync.

Required Input Files:

To use this method you will need two input files: a high-quality, final version of your video to use as the source file, and a time-coded caption file in SCC format. You can get the SCC file using our CaptionSync service, by selecting the Sonic Scenarist DVD Captions (.scc, .ndf.scc) as an output format. When you select this option you will receive two versions of the SCC file: one with drop frame time codes, and one with non-dropframe (NDF) time codes. Select the version of the file that matches the time coding of your video source file.

Setup in ProMedia Carbon:

1. The first step is to add the source file to your batch. Typically this will be an exported version of your final video in a ProRes or DNx codec. On the Source tab click Add, select the source file, and it will appear in the source list.

2. Next add the SCC closed caption file to the batch using one of Carbon’s video filters. Click Advanced -> Video Filters -> Add, and choose Caption Inject from .SCC File. Under this filter there is an option to select the SCC file on the right side. Select the file, click Open, then click Close to close the filter pane. Because the .SCC file is applied to the source file, the captions will be injected into all of the outputs in the batch.

3. Next click on on Target -> Add to select the settings for your target output files. You'll need to confirm with the stations or distribution networks that you are using the exact file format requirements, but you will find several common broadcast presets included with Carbon by default.

4. If you need other target formats you can add them to the batch in the same way.

5. Go to the Convert tab and click the Convert button, and Carbon will start generating your target files with encoded captions.