Adjust the volume of video slides
In Aperture, you can add video clips as individual slides in your slideshow. You work with video clips in the Slideshow Editor and Browser in the same way that you work with photos. However, there are additional controls in the Selected Slides pane of the Slideshow Editor for setting the volume of a video clip. For example, you can mute the audio clip in the main audio track while the video clip is playing. You can also change the duration of the fade-in and fade-out of the video clip’s audio to smooth out abrupt transitions between the video clip and the audio clip in the slideshow’s main audio track.
Note: To trim a video clip or duplicate it so that you can use multiple portions of it in the same slideshow, see Work with audio and video in the Viewer.
Change the volume of a selected video slide
Select a slideshow album in the Library inspector.
Select a video clip in the Browser.
Click the Slideshow Settings button in the lower-right corner of the Slideshow Editor, and click the Selected Slides button.
In the Selected Slides pane, do any of the following
To change volume: Set the volume of the video clip using the Volume slider and value slider.
To set a volume fade-in for a slide: Specify the duration of the fade-in, in seconds, using the Fade In slider and value slider.
To set a volume fade-out for a slide: Specify the duration of the fade-out, in seconds, using the Fade Out slider and value slider.
To reduce the volume of the main track while a slide plays: Select the “Reduce volume of main track to” checkbox, and use the slider or value slider to decrease or increase the volume.
To mute the volume of the main track while a slide plays: Select the “Reduce volume of main track to” checkbox, and set the slider or value slider to 0%.