Audio descriptions are additional information added to the audio track of a video during natural breaks in the audio part of the recording. These descriptions explain what is happening in the video that is not evident from the narration. See audio descriptions in action.
Audio descriptions are a newer technology.
Ideally, the video player that you use would allow you to upload two separate audio tracks, one that includes audio descriptions and one that does not. However, this function is not supported by YouTube.
The best strategy is to plan a video recording in which the narrator thoroughly describes what is happening on the screen. For example, in an instructional video, an instructor narrating a PowerPoint slide with a list of five important points would read the whole list, rather than just saying “As you can see, there are five important points.”
Alternatively, you can offer two separate versions of the video content, one with audio descriptions and one without.
Audio descriptions are created by editing the original audio track, adding the audio descriptions in the natural pauses and silences. Use a voice that contrasts against the existing narrative. This solution requires you to use video-editing software to re-sync the audio with the video track. See and hear how audio descriptions can be thoughtfully added to an existing audio track (9 min).