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QuickTime Movies and Resolution > QuickTime Movies and Resolution - Pg. 14

QuickTime Pro: Making It All Happen 14 As you might guess, higher resolution comes with a couple of "costs.' One cost is file size. The other is frame rate (covered in the next section). Higher resolution movies require larger files because each frame of the movie contains more infor- mation (more pixels). File size grows with a multiplication effect because resolution is measured by the number of pixels in the horizontal direction and the number in the vertical direction as in a resolution of 800 × 600 (a common resolution for smaller monitors). For example, an image with a resolution of 800 × 600 has 480,000 pixels of information in it. An image with a resolution of 1024 × 768 has 786,432 pixels of information or 306,432 more pixels of information per frame. Multiply this difference per frame by hundreds or thousands of frames per movie, and you can see why file sizes grow so quickly with higher resolution. Because higher resolution movies look better, you want to use as high a resolution for your movies as your means of distribution that movie can support. For example, if you are going to email a movie to someone, you don't want the file size to be huge, so you will need to create a lower resolution movie. If you are putting the movie on CD, you can handle a larger file size; therefore, you can create a higher resolution movie. If you are creating a movie for a hard drive, it can be even larger in file size. Fortunately, you can save movies you create at different resolutions for different purposes (you'll learn how when you get into projects later in the book). The resolution at which you create a QuickTime movie is called its Normal size (you learned how to change the size at which a movie plays earlier in the chapter). Because the amount of information in a movie (its resolution) is fixed, it looks the best at its Normal size or smaller.When you play a movie at its normal size, everything looks like it is supposed to.When you make a movie smaller, your Mac can simply "throw away" pixels that it doesn't need to display, and still the image looks good. However, when you make a movie larger than its Normal size, the image quality can degrade sig- nificantly. This is because your Mac has to create pixels that aren't really there to "fill up" the addi- tional viewing area. This can result in a blocky, Size is Relative A pixel does not have a defined physical size. The size of what you see onscreen depends on the resolution of your display. This is because all monitors have a fixed display area that is determined by the size of the monitor, such as a 17-inch or 22-inch. However, the reso- lution of the images displayed on a monitor can be changed. When the resolution is in- creased (say, from 800 × 600 to 1024 × 768), a larger number of pixels must be displayed in the same physical viewing area. The result is that the pixels "get smaller," so an image of fixed resolution will appear to be smaller on a display when it is set to a higher resolution. For example, if you watch a QuickTime movie on a display set to use a resolution of 800 × 600, it will appear to be a certain size (at its Normal size). Take the same movie and play it at its Normal size with a higher display resolution, such as 1024 × 768, and the movie will seem smaller because it is displayed using "smaller" pixels. When you choose a Normal size (resolution) for your movies, you need to keep the audience in mind. If you think that the audience will be using Macs with a typical display resolution of 800 × 600, you need to size your movie so that it looks good when displayed at this size. If you think most people will be viewing your movie with higher display resolutions, then you need to create higher resolution movies so they will look good then, too. rough looking image (more commonly called a pixellated image because you can see individual pixels). The bottom line to this is that you need to create QuickTime movies at the largest resolution at which you intend them to be viewed while keeping the file size at a reasonable level for the distribution method you are using. (This all sounds complex, but fortunately, the digital lifestyle applications manage this complexity as you will see when you get into the project chapters later in this book.)