[ This article was first published in the April, 2006, issue of
Larry’s Final Cut Pro Newsletter. Click here to subscribe. ]
Recently, on the Apple Trainer’s list-serve, a debate started about the function of Frame Offset.
According to Apple’s FCP 5 manual:
No matter what signal format you use for external monitoring, all digital video and audio interfaces (including FireWire) introduce inherent processing delays (known as latency) to signals sent out of the computer. External video and audio coming from the built-in FireWire port or third-party interface may be several frames later than the video on your computer display (in the Viewer or Canvas). The latency, or offset, between different devices can make precise editing difficult.
By changing the frame offset value in Final Cut Pro, you can compensate for the delay between your computer display and external video and audio outputs. Frame offset is active only when your sequence real-time effects are handled by Final Cut Pro
To view, or change, your Frame Offset, go to Final Cut Pro > System Settings and select the Playback control tab. Half-way down the screen is the default setting for the Frame Offset of 4 frames.
Now, here’s the important part. Changing the Frame Offset changes how long Final Cut delays displaying video and audio to your computer. It does NOT change any output sent through your FireWire port.
In other words, if you are watching video both on your external monitor and on your computer screen, and they are not in sync, changing the Frame Offset delays your computer screen to match your external monitor, based upon the number of frames entered in the Frame Offset. This is the opposite of how Avid handles these delays. On an Avid, changing the Frame Offset changes the delay to the external monitor.
Prior to researching this, my understanding of what was being delayed was incorrect and I wanted to share this revised information with you.
Martin Baker, from Digital Heaven in the UK, further comments:
However the Frame Offset setting is not useless if your monitoring is set up in the right way. As your original article says, it is crucial that the audio is monitored from the SAME point as the video. Therefore if you have an external FireWire converter or camera feeding a video monitor then you must also use the audio feed from that device for everything to be in sync.
Larry replies: This is why I recommend that my clients add an audio mixer to their editing suite, so that they can easily switch their speakers from monitoring the audio from their computer to monitoring the audio coming from the deck.
