When you create Group Clips, you have to tell Media Composer how the multiple clips should be synced together. The chapter on editing with Group Clips and MultiCamera Mode will discuss the specifics of syncing and Grouping clips that all share the same timecode (frequently referred to as Common or Jam-Synced timecode), as well as syncing and Grouping clips that may not share the same timecode, but do have a common reference point (for example, a Clapper Slate or the same audio).
Since syncing multiple clips that all share the exact same timecode is relatively easy, I thought an overview of two other methods of syncing clips so that they can then be used to create Group Clips would be helpful.
Using a Clapper Slate during production works like this. You would begin recording with all the cameras, making sure that they can all see the Clapper Slate. You would then Clap (also known as, Mark) with the Slate. The slate being clapped (that is, the two parts of the slate being banged together) provides both a visual and an audible common sync reference point when recorded by all the cameras at the same time. This is then used during editing to sync up the footage from the various cameras. If you’re really in a bind, and don’t have a Clapper Slate, you could position your hands parallel to the ground, one above the other, and clap your hands to provide a common sync reference point.
Once the cameras are recording, if at all possible, it is advisable not to stop them independently of each other. In other words, the most desirable thing is to have the cameras start and stop recording at roughly the same time. This will make the syncing process a great deal easier and faster. If this is not possible, it’s not the end of the world. It just means that there will be some additional work required. This additional work is introduced later in the Audio Waveform Display recipe.
Multiple cameras can also be synced by aligning their audio waveforms (presuming they all recorded the same audio, of course). The chapter on editing with Group Clips discusses how to do this manually by visually aligning the waveform displays. If you do a lot of MultiCamera editing with footage that does not have common (jam-synced) timecode, or even a common sync reference point (for example, a Clapper Slate), then you may want to investigate a Third-Party application called PluralEyes. It also syncs multiple cameras by analyzing the waveforms, but it potentially does it much faster than the manual method covered in the chapter. While I have not personally used this software, I have heard positive things about it, and it could be a big time-saver if you’re in this situation frequently.