Playing Around with Masks in QTPro
QuickTime Pro has a lot of nice functions, but I hardly ever use its more interesting features. I'd never tried masks in QTPro until today, but first used it to crop the UI from some old clips shot in V2, then used it to make an oddly shaped video from an unedited Melt clip. I also tried making a more elaborate mask but it was a big fail - probably too complex (big file), I suppose.
To make a mask you can take a still from your clip and open it in a graphics editing program such as Photoshop. It's a good way to start as then you can see what needs to go where, but if you are doing something simple you can wing it and just start with a blank canvas (I used the same size as my movie - I'm not sure if it would work or not with another size).
QuickTimePro's masking uses a black and white image in a format like gif, bmp, jpeg. Black parts will be visible video; white parts will be masked. Here's a cool thing: When you add a mask it shrinks to the unmasked area - creating a crop effect that has to be exported to be fixed and not just a reversable effect.
To crop the top UI bar out of my clip I covered the bar area of my screenshot with white and the video with black. I saved it as a gif, without doing anything to the settings. Back in QTPro I looked at Window --> Show Movie Properties and clicked Video Track to get a tab for Visual Settings. On that pane there's a big white square waiting for you to drop a mask on it. I dropped my mostly-black-with-a-white-bar-over-the-UI gif onto the square (well to be honest I just opened it with Choose) and the video immediately cropped itself. I exported it.
The odd shape was just a quick one that I did when my elaborate mask failed, but you get the idea: it was a big, black shape on a white ground, saved as a gif and applied in the same way. Cropping alone is very useful, but there's scope for much more with this easy mask function.
posted by - 1:22 AM