Working with closed-captioning audio objects

You can integrate closed-captioning in mp3, wav, ogg, f4v, and flv audio objects. The captioning text is displayed within the audio according to details specified within a caption file. You can set the color and opacity for the background and specify whether to display the caption box.

When captions are integrated into an audio object, the audio controller height increases by about 90 pixels to accommodate displaying the captioning text. Hidden audio and audio enabled without a controller will disable captioning. Closed captions can be disabled/off (displayed with the word “None”) or enabled/on (displayed with the word “On”). Regardless of the language in the caption file, the controller will show “None” or “On”. You can control if closed captions are displayed by default using the Display audio/video closed captions by default preference. For details about setting this preference, see Displaying audio/video closed captions by default. You can have custom fonts enabled within your organization. This allows you to ensure that the fonts you use within project will properly display in your users' browsers regardless of whether they have the font locally installed. For details, see Enabling custom fonts.

The program supports eXtensible Markup Language (XML) .

Select from three supported formats:

• Web Video Text Tracks (WebVTT) - Captioning format for HTML media players (Recommended)

  For full Firefox support with WebVTT, on the Web server where the project resides, set a mime type definition for VTT: AddType text/vtt .vtt

• SubRip Subtitle (SRT) - Popular standard used for YouTube and Facebook captioning

• eXtensible Markup Language (XML)

Examples of each format are provided below.

Additionally, you can customize the caption styling, including the font and font highlighting. The following font properties can be configured within the closed-captioning file:

Follow these rules when creating the captioning file:

• Specify the start and end times for each caption set. Time is in the format: hours:minutes:seconds:hundredths (HH:MM:SS:hhh)

• Specify the text for each caption set. Text can appear on multiple lines, if desired.

• Optionally, customize the font styling using a <span> tag.

• Save the file as a plain text file with the desired name and change the file extension to the appropriate captioning file format (.vtt, .srt, or .xml).

  For WebVTT, make sure there is a blank line between the heading and the caption details.

Sample files are provided to help you quickly get started creating and specifying the closed captioning file.

To create and specify a closed-captioning file:

1. Do one of the following:

   • In the Project Explorer, double-click the graphic of the audio object.

   • In the Project Explorer, right-click the graphic of the audio object and select Properties.

   • In the work area, double-click the audio object.

   • In the work area, right-click the audio object and select Properties.

2. On the Properties ribbon, click Add Captions in the Playback Options group. The Add Captions window opens.

3. For an existing captioning file, use the Caption File pull-down list to navigate and select the captioning file. Click to edit the file if necessary. To view a sample format file that you can edit and save to project, click one of the three file formats under Sample caption file formats. The WebVTT format (.vtt) is recommended. Click Save to Project when you are done editing the captioning file.

4. Select Display Caption Box to enable the appearance of the caption box.

5. Select the CC Background field to select the background color for the caption text and use the Opacity field to select the percentage of opacity. Select 0 to make the text completely transparent.

6. Click OK.

Examples

• WebVTT (Recommended)

  00:00:00.000 --> 00:00:00.000
<span style="text-align:center"></span>

00:00:08.000 --> 00:00:10.000
VTT Format: This line should appear at 8 seconds

00:00:10.500 --> 00:00:12.500
These two lines should
appear at 10.5 seconds

00:00:17.000 --> 00:00:20.000
These two lines should appear
with styling at <span style="color: #FF0000;font-weight: bold;">17 seconds</span>!

• SRT

  00:00:00.000 --> 00:00:00.000 <span style="text-align:center"></span> 1 00:00:08.000 --> 00:00:10.000 SRT Format: This line should appear at 8 seconds 2 00:00:10.500 --> 00:00:12.500 These two lines should appear at 10.5 seconds 3 00:00:17.000 --> 00:00:20.000 These two lines should appear with styling at <span style="color: #FF0000;font-weight: bold;">17 seconds</span>!

• XML

  <?xml version="1.0" encoding="UTF-8"?>
  <tt xmlns="http://www.w3.org/2006/10/ttaf1">
    <div>
      <p begin="00:00:00" end="00:00:00">
      <span style="text-align:center"></span>
      <p begin="00:00:08" end="00:00:10">
        XML Format: This line should appear at 8 seconds
      </p>
      <p begin="00:00:10.5" end="00:00:12.5">
        These two lines should
        appear at 10.5 seconds
      </p>
      <p begin="00:00:17" end="00:00:20">
        These two lines should appear
        with styling at <span style="color: #FF0000;font-weight: bold;">17 seconds</span>!
      </p>
    </div>
  </tt>

Additional resources: How to Add Closed Captions to Video and Audio in Lectora and Lectora Online

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