Audio-Video Sync in Captivate published movie
Audio makes your elearning content more engaging and useful to learners. You can add audio to your Adobe Captivate project either by recording yours or somebody else’s voice directly or by inserting a previously recorded audio file (.AVI, .WAV). When you add audio to a slide, it appears as a separate ‘element’ in the timeline. You can synchronize the audio with the slide by adjusting its timeline.
When you publish the project, Adobe Captivate embeds the audio within the output file. The embedded audio can be a single file or multiple files based on the timing and type of audio. Adobe Flash Player that plays the Adobe Captivate movie also plays the audio along with the movie.
Sometimes, you may notice a lag in the audio timing and that it is not synchronized perfectly with the movie. The audio that must ideally end with a slide spills over to the next slide. In this article, let’s examine why such issues occur and how they can be solved.
Why does this issue occur? Before understanding the reason for this issue, let’s first understand how Adobe Captivate publishes audio.
Whenever an audio starts and ends at the same time as that of the slides, Adobe Captivate ‘stitches’ up the audio objects on the contiguous slides into a single file when the project is published.
Suppose the audio on slide 1 runs till the end of the slide as shown below:
The audio on the next slide, slide 2 starts right from the beginning of the slide as shown below:
In such a case, the audio files on both the slides are ‘stitched’ and published as a single audio file. Similarly, if all the slides contain audio that start at the same time as that of the slides and spread till the end of slide, Adobe Captivate creates a single audio file in the published output.
Note: If the audio on the contiguous slides are of different types (mono and stereo), Adobe Captivate generates separate audio files for each of the types even if the audio starts and ends at the same time as that of the slides.
Adobe Captivate is designed to do so to logically stitch up users’ narrations that are done during or post-recording of a screen or application. A single audio file helps to keep the continuity in the narration intact.
Adobe Flash Player plays the Captivate published audio and stops only when the specified duration elapses or when you intervene and stop it. Therefore, with a single audio file in an Adobe Captivate movie, the audio and video run parallelly at their own pace resulting in synchronization issues.
Is there a workaround? Yes, a very easy one. Tweak the audio timing in such a way that Adobe Captivate generates and embeds multiple audio files in the output. To do so, extend the duration of the slide a little more than that of the audio. For example, if the current slide and audio duration is 4 seconds, extend the slide duration by another 0.3 seconds, and retain the audio duration at 4 seconds.
The following illustration shows the difference between the audio and the slide duration:
Now, Adobe Flash player can control the beginning of each audio file at the specified time in the movie.