Video
Multi-camera Mix - 4
Capturing and Synchronising
Once you've decided how long a section of the programme you're going to work on, you must capture the video from the fixed cameras and record the PA sound, each as a continuous file for the full duration. You must also capture the various hand-held shots, for which I suggest using the "capture and cut" technique I described in the last issue of Computer Video. Remember to adjust the video settings and sound levels correctly for each source, as described above.
Now you can start on the first step of the editing process. Open the Video Editor, and if it uses templates select one with the appropriate parameters.
Load
the video file from camera-1 first, and put it on track Va. Apply the
audio "Pan" filter to it, and set both the start and end to 100% left
channel
Next
load the other fixed camera video file into Vb, and also apply the "Pan"
filter to its audio track as with the camera-1 track, but set it to 100%
right channel for its entire duration
Plug a pair of stereo headphones into your computer instead of the speakers, set preview mode to "audio only", and preview a section of the timeline fairly near the beginning.
You will hear the PA in your left ear, and the camera sound in your right (if you don't, check that the audio settings for preview are for stereo mode). They will probably be some way apart, so adjust the position of one or other in the timeline to get them to the same point. As they get close, you can expand the timeline in order to adjust the clips accurately. Your ears are particularly sensitive to the synchronisation of sound in this way, anything as much as one frame out of sync. sounds like an echo. Passages containing speech, or percussive sounds such as footsteps, work best.
Now
move to near the end of the scene, and preview another section of audio.
You should find that the tracks are still in sync. I was pleasantly surprised
to discover how accurate the timing of modern video equipment is. In my
case, three separate cameras and a VCR showed no perceptible drift over
periods of up to 15 minutes. However, this is why you should avoid analogue
tapes for sound recording, because the speed accuracy will not be anything
like as good.
Now that you have synchronised the two video files, you no longer need the sound for the Vb track, so split the sound from the video, and delete the sound (right).
Now do the same thing with each separate hand-held shot. It's easiest to find the approximate location by viewing parts of the video, or just by looking at the frames in the filmstrip display. Then use the audio method to get exact synchronisation, putting the new clips on 100% right channel. After synchronising each one, split off the sound and delete it.
Finally, add the sound file of the PA to A2, and synchronise it in the same way. You can then remove the audio-pan filters from the two sound tracks. You should then have a project timeline looking something like below, which is shown with file-names instead of thumbnails for clarity.
All the video and audio tracks that are going to be used for the final mix are in place, exactly synchronised, and unused audio tracks are not present. If you haven't already saved this project, do so now! It has taken a lot of work to get to this point, and you don't want to lose it.
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