|Lately, I have been getting hired to supercharge sports footage. I create the spots for our IHL hockey team, The Chicago Wolves and while their budgets are narrow, hockey footage is plentiful. Each month I sift through their video game highlights and digitize the coolest clips for some digital frolics in After Effects. Much of this requires isolating the players from their backgrounds as a starting point for further embellishment.
Midway Games invited me to assist with their new baseball game, Slugfest. As with my hockey treatments, I had to manipulate MLB highlights for their DVD game intro. Take a look at the attached baseball clip to get a feel for the described treatments. You'll note that the players stand out from their backgrounds.
In the project file, I have included the baseball runner clip but because of its size I have not included a Light Storm clip. If you haven't already, you can create your own by referencing my Light Storm tutorial. Also, with all the labor involved in cutting out your figures it would be better if you use one of your own clips and follow along to make your characters jump off the screen.
Click to enlarge
In a perfect world, the bat boy would be chasing the baseball players around the field holding an evenly lit green screen behind them. This would make for a simple extraction using the color keyer. In the real world, the digital artist is forced to painstakingly cut the figures out frame by frame. There are a few ways to do this depending on the action but the results are always worth it.
Before any masking takes place you need to merge your fields together so you have hard progressive frames. This gives the footage a more cinematic look as it creates 30 pieces of information per second as apposed to videos 60 fields per second. This de-interlacing will also allow for a more accurate mask. To do this, simply highlight the footage in the footage window and open up the interpret footage panel. Select either lower or upper field first. In my case, I use the DPS Reality card which is lower field dominant.
Good. Now back to our masking choices.
For a slow moving figure or object, I animate bezier masks at different points in the action and create in-between points to see if the interpolation is on track. For a two second clip, I draw a mask (or combination of masks) on frame one (making sure to establish a keyframe) and then I shuttle up to the last frame and move the existing mask to fit the new shape. Then I go to the one second mark (mid-point) and contour the mask to fit the figures new shape and do the same for the in-betweens until the mask fits like a glove on all frames. This saves a lot of time because the mask should be in the ballpark (pun intended) on the in-between frames and, therefore, require less manipulation.
However, for fast moving figures as in a sports clip, the bezier masks will cross over each other and cause more trouble than they're worth. You will need to paint out each figure on every frame with Vector Paint. Yes, it is a laborious process but there is no shortcut to coolness.
Before beginning your long painting session, copy the clip and stack it below the painted clip so you have it as a clean background element. You can turn off the layer temporarily to keep the focus on your masked layer. We will affect it later.
Apply Vector Paint to the top layer. The Vector Paint control panel is fairly simple. I described it in a bit of detail in my Light Storm tutorial but for this masking task, we will only be concerned with brush opacity, feathering and resizing.
When you open the vector paint panel, playback mode should be set to Current Frame and composite paint should be set to Over Original. This will allow you to see both the paint and the original image. The color choice doesn't matter as it will only be used as a mask. I usually pick a color that is different from the footage I'm highlighting so it stands out.
Vector paint gives you great control over blurred and transparent areas. For a fast moving figure like the baseball runner there is plenty of blurring in his arms and legs. I keep one finger on the control key (windows) to quickly resize the brush and feather edges when needed. I start with a solid brush for the solid areas and then bring my transparency down to 50% or so to brush in the blurry parts. When the figure is completely covered, advance to the next frame and do the same. If you make a mistake and go outside the figure, Vector Paint allows only one layer of undo. If you miss that chance you can always use the eraser brush to eliminate the over spill.
Rotoscoping is about as exciting as laying bricks. It's extremely tedious but requires no thought. Put on some good music or talk radio before you begin this mind-numbing process and use a drawing tablet if you can. I am embarrassed to admit that the attached clip was painted with a clunky mouse. A drawing tablet will ease the pain in your aching wrist and speed up the process while offering greater control of your ever-changing brush settings.
Obviously the painting will be a bit sloppy which in my opinion adds to the coolness when played at speed. In fact if you're rushed or simply feeling lazy you can be intentionally sloppy and roughly slop paint over the figure frame by frame. I did some of this in the Saliva Video on my site.
Once you have all of the frames painted out, select as matte in the Vector Paint effects panel. This will drop out the background leaving the cutout figure. With the bottom layer turned off, you will see figure completely isolated. From here the possibilities are endless.
Turn on your background layer. You can blur the background, eliminate or change the color or affect it in other ways to make the foreground figure stand out. I used colorama (under image control) with one of the color ramp presets in the output cycle pulldown menu. Then, I added some side to side motion blur.
To make our runner more nuclear, add glow to the foreground cutout. Use glow based on Alpha Channel to really brighten the edges.
You could also duplicate the cutout, drop it under the main layer and use glow based on Color Channels. This will add a nice halo to the runner. Adjust the radius and intensity settings to taste and use a transfer mode (screen or add).
I also added a Light Storm clip between the baseball runner and the background. As mentioned in my Light Storm tutorial, you can use Bezier Warp to precisely bend the light storm to fit the scene.
There are many other options once you have your figure painted out with Vector Paint. A drop shadow on the foreground figure with a slightly blurred background will allow for a cool separation. Try using After Effects 3D to physically separate the clips while moving your camera around them. Add a spotlight to throw a drop shadow on the back layer. I did this with the Saliva video on my site. You'll also find more Slugfest clips on the site.
Discuss this technique or others in the After Effects forum at CreativeCOW.net.