Per bit rate settings, CBR tab

The following settings are applicable to a profile that uses CBR encoding.

• Audio format. Click a setting for the audio content. This setting determines the target audio bit rate, sampling rate, and whether the audio is intended for playback on mono or stereo speakers. A higher sampling rate yields higher-quality audio but requires more bandwidth or results in a larger file. Ideally, you want to achieve the right balance between bit rate and sampling rate. Remember that the audio stream must share the available network bandwidth with any video or script streams.
• 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 frames per second (fps) for the video stream. 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 setting and available bandwidth, the actual fps you achieve might be lower.
• Key frame interval. Type the number of seconds that you want to separate key frames. All frames between key frames are delta frames, 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 smoothness. Type a number from 0 through 100, with 0 yielding the smoothest image and 100 yielding the clearest image. Video appears smooth when objects move easily from one position to another on the screen and the edges of objects are not jagged. Video appears 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 frame rate, depending on the video. For example, if your video contains a lot of motion, increasing the clarity may decrease the frames per second.
• Video bit rate. Type the bit rate (in bits per second) you want to use for the video portion of your content. Type K for kilobits, M for megabits, or G for gigabits. The amount does not include the overhead required to accommodate network traffic. Remember that the video stream must share the available network bandwidth with any audio or script streams.
• Buffer size. Type the number of seconds that you want content to be stored before encoding begins. A larger buffer results in better quality content, but requires more memory. When you encode content, the encoding process is delayed by the amount of time specified in the buffer; the content is also delayed by the same amount of time when streaming to a player, such as Windows Media Player. When streaming a broadcast, the content played in the Player runs behind the live event by the amount of time that you specify in Buffer size.
• 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.