HDV:What You NEED to Know

          Remember the movie “The Matrix” and all of it’s incredible stop-action motion?* Or in the movie “Shrek” when the Princess is flying through the air, kicking the stuffing out of Robin Hood and his Merry Men? This visual effect is accomplished by mixing speeds, stop frame action, freeze frame, and a few other techniques. A similar effect can be accomplished using tools found in Vegas 2.0-5.0. This series of tools and techniques have been created in Vegas Video 3.0, known as “Velocity Filtering.” (This tool was also available in Vegas 2.0) Velocity filtering allows for media to speed up, slow down, reverse, or freeze frame, all without cutting clips of media into individual pieces as previously required in most applications. Velocity filtering or ‘envelopes’ as they are known in Vegas, may be applied to any number of clips. The speed at which the envelope interacts with the media can be controlled as well, via keyframes. Every effect, envelope, filter may be keyframe-controlled in Vegas 3.0, with a variety of shapes for the envelope properties.

We’ll start by placing media on the timeline. Download the project file,  and open in Vegas. (you’ll need to insert your own avi or quicktime in the place of original media. Original media is 20 seconds long though any length will auto trim) You can also use the  clip provided.

Notice on the timeline, there is a blue line in the middle of the first two clips. This is to demonstrate how the velocity envelope is adjusted. (footage courtesy of Artbeats)

The third clip space on the timeline is for you to do your own velocity envelope. Of course, you can do whatever you’d like with the project files too.

Start by previewing the first clip. Notice how it slows down during the first moments of the event, slowly climbs back to regular speed, and then freezes frame at the end?

In the second clip, the video actually will reverse to give an ‘instant replay’ type of feel. Again, the clip freezes frame at the end, allowing time for a blur, added title, special effect, or just a simple dissolve to the subject shot. This is especially effective with video of high motion such as sports, chases, fight scenes, etc. Notice how during the freeze frame, the pan/crop tool is used to create an artificial camera zoom. Another great space to use the velocity envelope is when you have a series of camera zooms that maybe weren’t as smooth as they could have been, as the envelope will slow down the jerkiness of a poor zoom, or speed up a zoom that was too slow. A velocity envelope applied to speed up a fast zoom makes it faster, more frantic, and draws immediate attention to the subject on the screen.

 

Now create your own velocity envelope and settings.

 

To insert a velocity envelope into a media clip, right click on the clip and select “insert/remove velocity envelope.” A blue line will appear. The line will be set by default to normal speed, or 100%. Double click on the timeline, and a node or “handle will appear. Move down the timeline a few seconds and double click again, inserting a second handle. These handles are like keyframes, allowing the setting of velocity or speed on the individual clip. Now, move the handle up or down to set the desired speed. If the desired percentage of speed change can’t be precisely achieved by moving the handle up and down, then right click on the handle. The dialog box shows the fade choices, and speed settings. Select “set to” and type in the desired setting.  Slow the envelope down just as the zoom reaches it’s end, and make sure the handle on the keyframe is set to ‘smooth if the media is being sped up or slowed down over a short number of frames. By setting the envelope handle to ‘smooth,’ the media won’t appear to jerk or jump from slow to fast or fast to slow.

          As the media is sped up or slowed down, artifacts may occur, particularly in Vegas 2.0. Avoid this by right clicking the clip, select “properties” and check the “resample” box. This will cause the render to slow down somewhat, yet will carefully resample the video to assure smooth picture and motion in most every instance.

          Velocity envelopes have been used for in nearly every form of special effect there is, and may be used for titles, movement control, color keying, and other forms of effect. One of my favorites is to use an envelope during a title shot, slowing or freezing the subject matter, panning/cropping the media as though the camera zoomed in on the subject, and dropping the opacity of the media so that the title can punch through. This is exceptionally effective when coupled with a mask and moving media behind the text. Velocity envelopes can be applied to all moving media, including .gif files.

          Another tip when using velocity envelopes on long files; use the split tool (‘s’ key) to split the clip prior to the insertion of the velocity envelope. Otherwise, the envelope will affect the entire file and slow down the render process, when only a small portion of the clip needs to be affected and resampled.

          Velocity envelopes are one of the least used, yet most effective tools in the Vegas application. Experiment with them, try them on slow and fast motion events to see what works best for you.

 

Happy "velocitizing,"