ptg16476052Hosting Your Own Video 39514
There are three ways to specify the quality for your video, and understanding them
requires that you know about bit rate. The bit rate of a video is the amount of data used
by one second of video. The bigger the number, the more space the video will use. The
default method of specifying quality is “constant quality.” What this means is that the
entire video will be compressed by the same factor. H.264 is like the JPEG image for-
mat in that some data is lost when the video is compressed. The Constant Quality set-
ting applies the same compression factor to the whole video. When you set a video to
Constant Quality, the video uses whatever bit rate is required to provide that quality, so
the bit rate will vary throughout depending on how well the video can be compressed at
the specified quality level.
The Average Bit Rate option varies the quality of the video to satisfy the bit rate that you
specify. Both it and the target file size option are more predictable—the video will be the
size you expect when you get to the end.
Instead of manipulating the settings on your own, you can use one of the presets that
HandBrake provides. To view the presets, click the Toggle Presets button on the upper
right. The list of settings in Figure 14.7 will appear. (I’ve fully expanded the list.) These
presets are already optimized for certain uses. The one that works best for web video is
the iPhone & iPod Touch preset. The simplest approach, if you’re starting out, is to select
it and then click the Web Optimized check box.
You’ll also want to click the Picture Settings button in the toolbar to specify the height
and width of your video. 320×240 is a pretty standard size for smaller videos. 640× 480
is also a common setting. For HD video, set the size to at least 1280×720. From Picture
FIGURE 14.7
The list of
HandBrake
presets.