Concept: Strobe a dynamic clip based on tempo of music
Module: VT-Edit
Assets: None
Time: 10 minutes

The temperatures are dropping, and causing visions of white and flights of fancy to dance through the minds of skiers everywhere. As its popularity grows, so too does the amount of video production for people to show when they get back from the slopes. If you come home this season with an armload of tapes, here is a VT-Edit trick to spice up selected portions of your video.

There are moments, such as the first time a skier catches serious air, that are worth highlighting from the rest of the footage, which leads us to this tutorial. With the use of a few real-time tools in VT-Edit, we can arbitrarily freeze a frame of video for a specific duration, and when the duration has elapsed, pick up the frame at that time segment in the original video clip.

Called strobing, that interval is often just an arbitrary length, of three to ten frames to create a jerky playback effect. But you can add some elegance to a strobe by tying its duration to narration, to sound effects or to the tempo of a music bed.

Launch VT-Edit

Bring in the video clip and music track

Trim the clips and set the audio clip beneath them in the timeline

In file bin, navigate to the VT[4] effects folder using QuickTab

Drag in the Hold Still filter beneath the clips, and stretch it to the length desired.

With the Hold Still filter (not the audio clip) selected, play the project and press ‘m’ at every point you want the strobe to refresh

Open Tool Shed from the VT-Edit button upper right, and go to Markers, Razor Cut

With the marked-up Hold Still filter selected in the timeline, click Perform. This replaces every marker with a cut, essentially creating a large number of smaller Hold Still filters in its place.

Toolshed allows us an ease to experiment with different timings of this concept as well. Undo all the markers in the filter by pressing Ctrl-z repeatedly, or you can right-click on a marker and in the context menu choose Remove all clip markers. If we wanted a strobe to happen every three frames, it would be impossible to press ‘m’ that fast. Again, Tool Shed comes to the rescue:

• With the Hold Still filter highlighted, press the Stop button on VT-Edit to jump to the first frame of the selected clip
  
• Tap the right keyboard arrow three times to advance three frames, and press ‘m’ to lay a clip marker on the Hold Still filter
  
• To establish an interval, advance three more frames and lay another marker.

Now, we could continue to lay markers in this fashion, but on a long clip, carpal tunnel could cripple us before we finish, so let’s use a faster method

• Open Tool Shed and go to Markers, Repeat Markers
• Check the option for Fill Ending. This will examine the three frame duration we have already established and proceed to lay a marker every three frames to the end of the clip (or filter, in this case)Go to Razor Cut (Markers) and press Perform.

You may notice the strobing, but it is mighty subtle only spaced at three frames apart. Let’s modify this quite simply

• Press ctrl-z three times to return to only one marker on the filter
  
• With the time bar on top of the marker, advance forward five frames, and press ‘m’
  
• Repeat the above steps to first repeat markers to the end of the clip and then to cut markers.

A duration of five frames causes the strobing to become much more evident.

This is a process that could have other applications as well, such as trying to view security camera footage that multiplexes numerous cameras, one image in each frame of video. When you play this back in VT-Edit, it just becomes a blur of multiple images, but applying this tutorial would allow you to hold the video playback of camera 1 until the next frame appears in the clip.

See what else you can do with the real-time capabilities of VT-Edit and Tool Shed!