Quality-based VBR tab
The following settings are applicable to a profile that uses quality-based VBR encoding.
- Audio format. Click the quality level you want to maintain for the audio content. This setting also determines the and whether the audio is intended for playback on mono or stereo speakers. A higher-quality setting yields higher-quality audio but increases the size of the output file.
- Video size. Type the size (in pixels) you want to use for the encoded video. Use numbers from 16 through 2000. The frame size of the encoded video will be resized to match the size you specify. Select the Same as video input check box to match the frame size of the source video.
- Frame rate. Type the number of frames per second (fps) for the video content. The amount that you adjust this value to depends on the speed of your computer processor and whether you are encoding high-motion or low-motion video. High-motion video generally looks smoother if you use a higher frame rate, but a higher frame rate increases the amount of work the processor must perform. The setting you specify represents the maximum fps. Depending on factors such as the video size and codec quality setting, the actual fps you achieve might be lower.
- Key frame interval. Type the number of seconds that you want to separate . All frames between key frames are , which are considerably smaller than key frames but have poor visual quality. 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, the size of the video increases. Increase the key frame interval for content with a static background, such as cartoons. Decrease the key frame interval for high-motion content, such as a sporting event.
- Video quality. Specify the image quality that you want to maintain by typing a value from 0 through 100. While encoding, the bit rate is adjusted as necessary to achieve the quality level that you specify without dropping any frames. Currently, there are 30 discrete quality settings, so several quality levels refer to each quality setting. The following quality levels equate to discrete quality settings: 1, 4, 8, 11, 15, 18, 22, 25, 29, 33, 36, 40, 43, 47, 50, 54, 58, 61, 65, 68, 72, 75, 79, 83, 86, 90, 93, 97, and 100. The numbers between two values equate to the same quality setting as the lower number. For example, 2 and 3 both equate to the same quality setting as 1.
- Decoder complexity. If you are targeting a hardware device other than a computer, you can specify a category of complexity for the content being encoded. Some hardware devices only support certain categories. (Refer to the documentation for your device for more information.) Note that the Complex option is intended for playback on computers. Typically, you should select Auto, which enables the correct complexity setting to be selected automatically during encoding.
- Script bit rate. Type the bit rate (in bits per second) that you want to use for scripts. The value must be between 1,000 bps and 10,000 bps. Type K for kilobits.
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