Using the Change Speed Dialogs

The Change Speed dialog (and the related Change Speed Segment dialog) are central tools for creating speed effects such as slow motion, fast motion, and changes in the speed of a clip over time. This section covers both the user interface (see About the Change Speed Dialogs) and specific ways to apply speed effects with these dialogs (see Applying Speed Effects with the Change Speed Dialog).

About the Change Speed Dialogs

You can create speed effects in an entire clip or a segment of a clip using the Change Speed command (available in the Modify menu) or the related Change Speed Segment command (available in a shortcut menu from the Clip Keyframes bar in the Timeline).

Note: The Change Speed dialog affects the speed for an entire clip. The Change Speed Segment dialog affects the speed for a single speed segment, a section of a clip between speed keyframes.

Figure. Change Speed dialog.
  • Duration: Use the Duration field to enter a new duration for the selected clip. The clip speed (in the Rate field) will be adjusted accordingly. For more information on the relationship between clip duration and clip speed, see Speed Basics. If multiple clips are selected, the new duration will be the duration of the first selected clip.
  • Original: This read-only text field displays the current duration (before you make any speed/duration changes).
  • Rate: Use this field to enter a speed percentage for a clip or a speed segment. A value of 100% indicates no change; in other words, the clip remains at its default speed. Values under 100% create slow motion. Values over 100% create fast motion.

    Tip: If you are using a Change Speed dialog to adjust a clip to a specific duration, use the Duration field rather than the Rate field to maximize precision.

  • Reverse checkbox: Select this checkbox to make the clip or speed segment play in reverse, using any speed specified by the above controls. When you do this, the numbers in the Rate field are displayed in red, to further warn you that the clip will play in reverse.

    Note: Alternatively, you can enter a negative value in the Rate field to make the clip or speed segment play in reverse. If you do this, the next time you open the Change Speed dialog, the Reverse checkbox will be automatically selected and the value in the Rate field will be positive rather than negative.

  • Start buttons: Use these buttons to affect the rate of change in speed at the beginning of a clip or speed segment.
    Figure. Start buttons in the Change Speed dialog.
    • Linear From Start button: Applies the default (constant) speed to the beginning of a clip or speed segment.
    • Curve From Start button: Applies a smooth change in speed to the beginning of a clip or speed segment. This is a quick and simple way to add a Bezier handle to the keyframe at the beginning of a clip or speed segment in the Speed parameter of the Motion tab in the Viewer.
    • Curve Centered on Start button: Applies a smooth change in speed starting at the end of the previous speed segment and continuing through the beginning of the selected speed segment. This is a quick and simple way to add a Bezier handle to the keyframe at the beginning of a clip or speed segment in the Speed parameter of the Motion tab in the Viewer.
    • Custom button: Final Cut Pro highlights this button automatically when you adjust the Bezier curve in the Speed parameter of the Motion tab.
  • Start Smoothing: Use this field to adjust the degree of speed smoothing in the beginning of a clip or speed segment. This setting affects the Bezier handle length in the Speed parameter of the Motion tab in the Viewer. The greater the value, the more effect the setting has.
  • End buttons: Use these buttons to affect the rate of change in speed at the end of a clip or speed segment.
    Figure. End buttons in the Change Speed dialog.
    • Linear to End button: Applies the default (constant) speed to the end of a clip or speed segment.
    • Curve to End button: Applies a smooth change in speed to the end of a clip or speed segment. This is a quick and simple way to add a Bezier handle to the keyframe at the end of a clip or speed segment in the Speed parameter of the Motion tab in the Viewer.
    • Curve Centered on End button: Applies a smooth change in speed starting at the end of the selected speed segment and continuing through the beginning of the next speed segment. This is a quick and simple way to add a Bezier handle to the keyframe at the end of a clip or speed segment in the Speed parameter of the Motion tab in the Viewer.
    • Custom button: Final Cut Pro highlights this button automatically when you adjust the Bezier curve in the Speed parameter of the Motion tab.
  • End Smoothing: Use this field to adjust the degree of speed smoothing in the end of a clip or speed segment. This setting affects the Bezier handle length in the Speed parameter of the Motion tab in the Viewer. The greater the value, the more effect the setting has.
  • Ripple Sequence checkbox: Select this checkbox to enable automatic rippling of the sequence when you adjust the speed/duration of a clip. Clips and markers later in the Timeline will move with the Out point of the speed-adjusted clip to prevent a gap or a collision in the Timeline.

    All clips coming after the adjusted clip ripple forward or backward according to the ripple editing rules in Final Cut Pro. For more information about rippling clips in a sequence, see Performing Slip, Slide, Ripple, and Roll Edits.

    Note: This automatic rippling feature is available in the Change Speed dialog only, and only for a single clip at a time. Automatic rippling is not available for Paste Attributes operations, nor for selections of multiple clips.

  • Frame Blending checkbox: Select this checkbox to smooth out the apparent motion of a clip playing back in slow motion. For more information, see Frame Blending, Optical Flow, and Motion Blur.
  • Scale Attributes checkbox: Select this checkbox to scale time-based clip attributes such as markers and keyframed effects. The attributes will be distributed proportionally in the speed-adjusted clip.
  • Remove Speed button: Click this button to remove all clip speed changes and restore a clip to its original, default speed.

    Remove Speed applies to entire clips only. This button is not available in the Change Speed Segment dialog.

    Note: To remove speed changes with the ripple option, you must use the Change Speed dialog. The ripple option is not available when you remove speed changes in any other fashion (such as with the shortcut menu, the Speed parameter in the Motion tab, or the Remove Attributes command).

Applying Speed Effects with the Change Speed Dialog

Follow the steps below to create speed effects with the Change Speed dialog or the Change Speed Segment dialog. The only difference between the Change Speed dialog and the Change Speed Segment dialog is that the Change Speed dialog affects entire clips, whereas the Change Speed Segment dialog affects only the section between two keyframes.

Note: The Change Speed dialog is the quickest and easiest way to apply a constant speed change to an entire clip.

To change the speed of an entire clip using the Change Speed dialog
  1. Select one or more clips in the Timeline or the Browser.

    Note: If the clips have existing speed settings, they will be replaced by the adjustments you make in the Change Speed dialog.

  2. Choose Modify > Change Speed (or press Command-J).

    The Change Speed dialog appears.

    Figure. Change Speed dialog.
  3. Use any of the controls in the Change Speed dialog to create the speed effect you want.

    For detailed information on each of the controls, see About the Change Speed Dialogs.

    Note: This automatic rippling feature is available in the Change Speed dialog only, and only for a single clip at a time. Automatic rippling is not available for Paste Attributes operations, nor for selections of multiple clips.

  4. Click OK.

The speed effects are applied to the clip. Depending on the settings you chose, the clip may be extended or shortened in the Timeline, and those changes may be rippled throughout the sequence.

Note: If maintaining video and audio sync is a priority, select both the video and the (synced) audio and apply constant speed changes only. Applying variable speed settings to a video clip (including speed segments, the Curve buttons in the Change Speed dialogs, and the Curve options in the Change Speed shortcut menu) will break the link to audio items. Audio and video sync is lost when you apply variable speed changes.

To change the speed of an individual speed segment using the Change Speed Segment dialog
  1. Make sure both of the following are true:

  2. Do one of the following to display the keyframe graph area and the speed indicator tick marks.

    • Click the Clip Keyframes control in the lower-left corner of the Timeline.

    • Press Option-T.

    The keyframe graph area is displayed below each clip in the Timeline. You can use this keyframe graph area to view and edit keyframes for applied effects. By default, the keyframe graph area includes the speed indicator tick marks. The spacing and color of the tick marks in the speed indicator area indicate the speed and playback direction of your clips. The speed indicators of clips in the Timeline update in real time as you make speed adjustments to clips in your sequence, showing you how you’re altering a clip’s timing.

    Figure. Timeline showing an applied speed keyframe in the speed indicator area.

    Note: To have the keyframe graph area and speed indicator tick marks displayed by default in new sequences, choose Final Cut Pro > User Preferences > Timeline Options and select the Clip Keyframes checkbox and the Speed Indicators checkbox.

  3. Control-click the speed segment (a section between two speed keyframes) that you want to change.

  4. In the resulting shortcut menu, choose Change Speed Segment.

    The Change Speed Segment dialog appears.

    Figure. Change Speed Segment dialog.
  5. Use any of the controls in the Change Speed Segment dialog to create the speed effect you want.

    For detailed information on each of the controls, see About the Change Speed Dialogs.

  6. Click OK.

    The speed effects are applied to the speed segment.

Keep the following points in mind when you use speed keyframes and speed segments:

  • Any change you make to an individual speed keyframe will alter the segments to the left and the right of the keyframe, but it will leave all other speed segments unchanged.

  • If maintaining video and audio sync is a priority, select both the video and the (synced) audio and apply constant speed changes only. Applying variable speed settings to a video clip (including speed segments, the Curve buttons in the Change Speed dialogs, and the Curve options in the Change Speed shortcut menu) will break the link to audio items. Audio and video sync is lost when you apply variable speed changes.

If you use the Change Speed Segment dialog frequently, it might be useful to create your own keyboard shortcut or button (in a button bar) to open the Change Speed Segment dialog.

To create a keyboard shortcut or button for opening the Change Speed Segment dialog
  1. Choose Tools > Button List.

  2. Enter “segment” in the search field.

    The Change Speed Segment command appears.

  3. Select the Change Speed Segment command.

  4. Do either or both of the following:

    • While the command is selected, enter a keyboard shortcut.

    • Drag the command to a button bar to create a button.

Frame Blending, Optical Flow, and Motion Blur

Duplicating frames to create slow motion can result in a strobing, jittery effect. To minimize this, you can turn on frame blending in the Change Speed dialogs. When slow motion is created, frame blending uses the two frames that appear to either side of duplicate frames and creates new in-between frames that are a composite of both. When blended frames are inserted in place of frames that have simply been duplicated, slow-motion clips appear to play back more smoothly. Speed changes can still play back in real time with the Frame Blending option turned on.

Figure. Diagram of two images combined to create a single blended frame.

While clips using frame blending can play in real time at preview quality, frame blending on a field-per-field basis is much more processor-intensive and is only performed when the clip is either rendered or played via a third-party video interface with real-time hardware processing that’s capable of field blending.

For the most sophisticated slow-motion effects, consider using the optical flow technology available in the Timing controls feature in Motion and the Frame Controls feature in Compressor. For more information, see the Motion User Manual, available in Motion Help, and the Compressor User Manual, available in Compressor Help.

Smoothing Slow Motion Using Motion Blur

Although using frame blending is an excellent way to smooth out the apparent motion of a slow-motion clip, extremely slow speeds such as those below 20 percent can still result in strobing. To further minimize this effect, you can use the Motion Blur attribute in the Motion tab.

Drag the Samples slider to the right until you achieve the amount of blur you need to cover the strobing of your clip (the higher the Samples setting, the longer rendering takes) and then adjust the % Blur setting until you strike a good compromise between the sharpness of the clip and the smoothness of the motion.