Choosing the frame rate and video quality
Select settings for each video bit rate in the profile. Click the tabs at the bottom of the page to switch between video bit rates.
- Frame rate. Set the number of frames per second for the video stream. The amount that you adjust this value depends on the speed of the computer’s processor and whether the computer is encoding high-motion or low-motion video. High-motion video generally looks smoother if you use a higher frame rate, but the more frames per second your computer is required to encode, the harder the processor must work. The setting you specify represents the maximum frames per second. Depending on factors such as the video quality setting and available bandwidth, the actual frames per second you achieve might be lower.
- Key frame interval. Determine the number of seconds that you want to separate key frames. All frames between key frames are called delta frames. Delta frames contain only the part of the image that changed from the key frame. Delta frames are considerably smaller than key frames but their visual quality is poor. If you increase the time between key frames, the size of the video (in bytes) gets smaller because fewer key frames are used. If you decrease the time between key frames, more key frames are used and the size of the video (in bytes) gets larger. Increase the time between key frames for content, such as cartoons, with a static background. Decrease the key frame interval for high-motion content, such as a sporting event. The default setting is eight seconds for lower bandwidths and fewer seconds for higher bandwidths.
- Video quality. To fine-tune the image quality, use the video quality slider. You can emphasize either smoothness or clarity of images. Video content is smooth when objects easily move from one position to another on the screen and the edges of objects are not jagged. Video content is clear when images and motion are well-defined and clearly delineated. As you increase the clarity, the video becomes less smooth. Keep in mind that increasing the clarity can affect the frames per second, depending on the video. For example, if your video has a lot of motion in it, increasing the clarity may decrease the frames per second.
Note If you make changes to these settings, encode and play the content to test its quality before delivering it to users.
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