Retiming Audio

Motion allows you to retime audio clips or individual channels to speed them up, slow them down, or play them back at a different speed. All of the controls below can apply either to a stereo audio clip, or individual channels.

Note: When retiming video, audio attached to the footage is automatically retimed along with it. You can unlink video and audio to retime them separately. For more information on retiming footage, see Retiming.

Timing Controls in the Inspector

Each audio object has individual timing parameters in the Properties tab.

  • Speed: Sets the speed of the audio clip as a percentage. The default is 100%. Values lower than 100 play back the audio clip more slowly than its original speed, and also extend the Duration of the audio clip. Values higher than 100 play back the audio clip faster than its original speed, and shorten the Duration of the audio clip.
  • In: Sets the In point of the audio clip. Adjusting this parameter always moves the audio clip In point to the specified frame without affecting its duration.
  • Out: Sets the Out point of the audio clip. Adjusting this parameter always moves the audio clip Out point to the specified frame without affecting its duration.
  • Duration: Sets the total duration of the audio clip. Adjusting Duration will also affect the Speed and the Out point.
  • End Duration: Sets the number of frames by which the clip is extended at the end of its duration. This value may be adjusted only if End Condition is set to a value other than None.

Adjusting a Track’s Speed in the Timeline

Motion allows you to change the timing of audio tracks in the Timeline as well.

Important: To affect all channels of a multichannel audio file, select all the tracks in the Audio tab (press Command-A) before making adjustments in the Timeline.

To shorten the audio clip’s duration and speed up its playback
  1. Move the pointer over the end of the green audio track.

  2. Press and hold down the Option key.

    The pointer turns into the retiming pointer.

    Figure. Timeline tab showing audio clip being shortened with the retiming pointer.
  3. While continuing to hold down the Option key, drag the end of the track bar (the right end of the bar) to the left.

    As you drag, the tooltip displays the clip’s duration and speed.

To lengthen the audio clip’s duration and slow its playback
  1. Move the pointer over the end of the audio track in the Timeline.

  2. Press and hold down the Option key.

    The pointer turns into the slip pointer.

  3. Drag the end of the track bar to the right.

    As you drag, the tooltip displays the clip’s duration and speed.

Looping an Audio Clip

Another way of extending a clip’s duration is by looping it. You can easily loop a clip by adjusting it in the Timeline. When a looped audio clip reaches its last frame, the audio starts playing again from its first frame.

To loop an audio clip
  1. Move the pointer close to the end of the audio track in the Timeline.

  2. Press and hold down the Option and Shift keys.

    The pointer turns into the loop pointer.

    Figure. Loop pointer hovering over the end of an audio track in the Timeline.
  3. Drag the end of the track bar to the left.

    Figure. Timeline tab showing audio track being looped.

    As you drag, the tooltip displays the clip’s In and Out points, duration, and loop duration. A looped clip has barriers to indicate where loops begin and end in the Timeline.

    Figure. Timeline tab showing audio first loop barrier.

    The first loop barrier in a clip’s bar is interactive. Moving the barrier changes the point at which the clip loops.

To change the loop point of an audio clip
  • Drag the first loop barrier left or right.

    The end point of the clip’s loop moves as you drag.