Linked Sync Relationships Between Video and Audio Clips

Linking helps you keep video and audio clip items in sync. Clip items from the same media file are automatically linked to each other in the Timeline. You can also link unrelated clip items together.

Final Cut Pro keeps track of the sync relationship between video and audio clip items of all QuickTime media files that you’ve captured or imported into your project, as well as the sync between merged clips.

When video and audio clip items are linked in the Timeline:

When Linked Clips Are Moved out of Sync

When you move clip items in the Timeline, Final Cut Pro checks to see if the relationship between linked items is still correct. If the relationship does not match, Final Cut Pro displays out-of-sync indicators in the Timeline. Out-of-sync indicators show the offset between the linked clip items.

Figure. Timeline window showing an out-of-sync indicator for a clip whose audio has been moved in the audio track.

Even when clip items are unlinked, Final Cut Pro keeps track of the relationship between clip items that come from the same media file. This means that you can move those items out of sync at any time, without worrying that you won’t be able to resynchronize them later if you change your mind. Since merged clips contain clip items that do not come from the same media file, out-of-sync indicators are not shown when you unlink and move merged clip items. (For more information, see Merging Clips from Dual System Video and Audio.)

An out-of-sync indicator appears whenever the following conditions occur:

  • Audio and video clip items from the same media file are out of sync. Because they come from the same media file, these items always show out-of-sync indicators, even if they are not currently linked.

  • Audio and video clip items belonging to a merged clip have been moved out of sync. Because they come from different media files, these items only show out-of-sync indicators if they are linked.

  • Audio and video clip items have been linked together in the Timeline, and then moved out of sync.

Audio and video clip items that have a sync relationship must be vertically overlapping in the Timeline for out-of-sync indicators to appear when the items are moved out of sync. No indicator appears if linked audio and video clip items are so far apart that they no longer overlap.

Figure. Timeline window showing a selected clip whose audio item has been moved away from the video item.

If you move these items back together so that they overlap, the indicators appear again.

Figure. Timeline window showing a clip whose out-of-sync indicators appear once its audio is moved back under the video item.

This also works with multiple instances of clips from the same media file on disk. For example: You have three items in your sequence, all from different parts of the same media file.

Figure. Timeline window showing two video items and an audio item in a sequence.

If you move the audio item to the left, so that it overlaps the first video item, out-of-sync indicators appear. The same happens if you move the audio item to the right.

Figure. Timeline window showing an audio item being moved left under a video item, which causes out-of-sync indicators to appear.
Figure. Timeline window showing the same audio item being moved right under a video item, which causes out-of-sync indicators to appear.

What if you move all three items so that they overlap, but all are out of sync with one another? The first two items show out-of-sync indicators relative to one another, and the third item shows an out-of-sync indicator relative to the item it overlaps.

Figure. Timeline window showing three clip items with out-of-sync indicators.

Understanding Sync Relationships Between Multiple Linked Audio Items

Up to 24 audio items can be linked to a single video item in the Timeline. As a result, some complex sync relationships may result if you slip more than one of a clip’s audio items (for information on slip edits, see Slipping Clips in the Timeline). These are easily managed using the same out-of-sync indicators described earlier.

When you create a merged clip, or link multiple items together in the Timeline, the video item is considered the anchor item to which the sync of all other linked audio items is compared. If you’re linking audio clip items without a video item, then the topmost audio item in the Timeline acts as the anchor item.

In the following example, three stereo pairs of audio items are linked to a single video item.

Figure. Timeline window showing three stereo pairs of items linked to a single video item.

Moving a single pair of items out of sync results in a single out-of-sync duration, with out-of-sync indicators with positive and negative durations in both the video and audio items.

If you then move a second pair of audio items out of sync by a different amount, each audio item that is out of sync from the anchor item has an out-of-sync indicator noting its individual offset from the anchor item—in this example, the video item. The anchor item displays a mixed-sync indicator with no duration. This tells you that multiple linked items are out of sync by varying amounts.

Figure. Timeline showing a video clip item with a mixed-sync indicator and audio clip items with out-of-sync indicators.