Movie Options
The Movie Options Inspector lets you change settings of selected movies in the Storyboard/Timeline. You can make changes to multiple movies at once by selecting several movies in the Storyboard/Timeline before adjusting settings in the Movie Options Inspector.
The Movie Options Inspector opens automatically when you double-click a movie in the Storyboard/Timeline.

File
When a single movie is selected, the filename of the movie will be displayed here. If you want to replace the movie while keeping all other parameters, select the
. command from the popup menu next to the filename. You can also select to Reveal the movie file in the Finder, or Get Info on the movie.Volume
Controls how loud the audio of the movie is playing. Set it to 0% if you want the movie to be completely silent, because you have a song in the audio track instead. Drag the volume slider or enter a percentage in the text box.
Ducking
When Ducking is enabled, then the volume of other audio tracks is lowered by the specified percentage while the movie is playing. This is useful to lower the volume of a song in the music track, so that live sound from the movie can be heard more clearly.
Specifying a ducking factor of 100% means that other audio tracks are completely muted while the movie is playing.
Border
Use this feature to add a border to the movie of the selected slides. This allows you to select a border color from the Color palette and drag the slider or enter a point size to enlarge or decrease the width of the border.
Color
Use this feature to apply non-destructive color correction to the movies of selected slides. Color correction can be used to modify the color tint, saturation, and lightness (gamma) of a movie.
Click the Custom color button to open a popover. In the Color palette wheel, click and drag the black circle to the preferred color, and use the saturation and lightness (gamma) sliders to adjust these parameters. The movie in the Stage adjusts automatically as you make changes.

In the popup menu you can select to copy and paste the chosen color correction from one movie to another, or reset to go back to the original color in the movie.
The effects of the color correction are visible live in the Stage and Storyboard/Timeline. If you have multiple slides selected, the Stage does not display a movie, so the effects are only visible in the Storyboard/Timeline.
If you have several movies of matching color tint, but a few stick out with a different tint, you can select these movies and adjust their tint to match the other movies.
To create a black & white version of a movie simply reduce the saturation to 0%.
Range
Set in and out points to restrict the portion of the movie to be played. This is done by dragging the Range triangles inward. Only the light portion of the bar (between the triangles) will be played. The movie file itself will not be modified, so all changes can be undone at any time. The movie in the Stage adjusts automatically as you make changes, displaying the in point on the left side and the out point on the right side.
For more precise control over in and out points, you can enter an exact in point or out point. From the popup menu select Finetune In Point or Finetune Out Point or double-click on the in point or out point triangle to open a popover to enter an exact timecode.
Mask
Use a mask to crop an image to a specific frame. This cropping is non-destructive (i.e. the image file is never modified) so you can change your mind about the cropping at any time. Click on the button to reveal a popover that contains the options like mask type, size, edge softness. The popup menu to the right contains several convenient shortcuts to assign a mask to a layer.

When a layer has a mask, a switch appears in the Stage next to the zoom and rotation jogwheels. Switch it to "Mask" if you want to modify the zoom or rotation of the mask rather than the zoom or rotation of the image itself.

The aspect ratio of a mask is determined by the size parameter. However, the absolute dimension of the mask as it appears on the Stage also depends to the Zoom value.
Note that masks can be animated (just like an image layer can be) to achieve various interesting effects.
The popup menu to the right contains several useful command to quickly assign a mask to a layer.
Visibility
Use the Visibility controls if you don’t want a movie layer to be visible during the whole duration of a slide. Drag in the darker triangles (located on the outside) to restrict visibility to a certain range. Drag the lighter triangles (located on the inside) (creating a ramp in the curve) to fade-in and fade-out the movie layer. The yellow sections in the bar represent the incoming and outgoing transition intervals.

Dragging the upper horizontal black line downward lets you change the layer opacity. Clicking anywhere on the white bar opens a popover that lets you enter the values numerically.

The popup menu to the right contains several useful presets: Reset, Fade In, Fade Out, Fade In/Out.
Animation
When animation is enabled in the Slide Options Inspector, you can use the Animation controls to fine tune animation timing. The darker triangles (located on the outside) determine when an animations begins and ends. The lighter triangles (located on the inside) adjust the fade-in and fade-out of the animation. Refer to Fine Tuning Animation for more details.