Overview
The Audio Description (AD) Plugin for Closed Caption Creator enables broadcasters, post-production studios, and accessibility professionals to author described-video content using lifelike synthetic voice. Rather than relying on a separate application for AD authoring, Closed Caption Creator combines the subtitle editor, voiceover rendering, audio mixing, and export tools into a single unified workspace.
What the AD Plugin Provides​
The AD Plugin gives you access to over 100 synthetic voices from Amazon, Google, and Microsoft, covering more than 50 languages. These voices can be previewed, filtered, and assigned to individual events directly inside the application. Once text is written for an event, audio is rendered automatically in the background. The resulting voiceover can be previewed alongside the program audio in real time, with the volume of each source controlled independently through the media player's dual-slider volume control.
When the project is ready for delivery, the export workflow generates individual voiceover track files for each event, a combined VO mixdown, and a final program mixdown that embeds the AD audio against the original program audio. The entire mix is processed with configurable auto-ducking and loudness normalization to meet broadcast standards such as EBU R128 and ATSC A/85.
Requirements​
The Audio Description Plugin requires an active subscription. Because the plugin relies on desktop audio processing through FFmpeg and direct file system access, the desktop version of Closed Caption Creator is strongly recommended for production workflows. A web browser version is available but has limited export capabilities compared to the Electron desktop application.
Setting Up Your First AD Project​
When you create a new project in Closed Caption Creator, the application generates a subtitle Event Group by default. To work with audio description, you will either convert the Group Type of an existing group or create a dedicated Audio Description Event Group alongside it.
To create a new Audio Description Event Group, go to File → New → Event Group. In the Group Type dropdown, select Audio Description and provide a recognizable display name such as "AD English." Several subtitle-specific validation settings — including overlap detection, illegal character detection, and reading rate limits — are not relevant for AD work and can be set to permissive values (for example, setting the reading rate to 9999 and the minimum event duration to zero) to prevent false error flags during authoring.
Once the group is created it appears as a tab in the Event Group navbar above the Event List. Multiple AD groups can coexist in the same project, allowing you to manage descriptions in different languages or for different delivery targets within one session.
Interface at a Glance​
The Closed Caption Creator interface is laid out with the media player on the left, the Quick Tools panel beneath it, and the Event Editor on the right. The timeline runs along the bottom and can be toggled on or off using the timeline toggle in the top-right corner. The Voices tab within the Quick Tools panel is the primary access point for browsing, pinning, and assigning synthetic voices. The Event List on the right displays each individual AD event with its start time, end time, speaking rate, description text, voice assignment, and optional notes.