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Video options for encoding
In the Export Settings dialog box, the options available in the Video tab depend on the format you've specified. Video
settings include some or all of the following options:
Specifies the codec used to encode the video from those available on your system.
Codec
Specifies the encoding quality. Generally, higher values increase rendering time and file size.
Quality
Enables encoding of an alpha channel into the exported file for formats, such as Adobe Flash
Encode Alpha Channel
Video, that support alpha channels.
Conforms the output to the NTSC or PAL standard.
TV Standard
Scales the output frame's horizontal aspect to the specified width.
Frame Width
Scales the output frame's vertical aspect to the specified height.
Frame Height
The output frame rate for either NTSC or PAL formats.
Frame Rate
Specifies whether the output file's frames are interlaced, and if so, whether the upper or lower field is first
Field Order
in the scanning order.
Specifies the ratio of each pixel's width to height, which determines the number of pixels required
Pixel Aspect Ratio
to achieve a given image aspect ratio. Some formats use square pixels, while others use nonsquare pixels.
Specifies whether the codec achieves a constant or variable bitrate in the exported file:
Bitrate Encoding
•
Constant Bit Rate (CBR)
with a fixed data rate. Therefore, frames containing more complex data are compressed more, while less complex
frames are compressed less.
•
Variable Bit Rate (VBR)
amount of compression degrades the quality of a complex image more than it degrades the quality of a simple image,
VBR encoding compresses complex frames less and compresses simple frames more.
In general, an image is complex and more difficult to compress efficiently if it contains great detail or if it differs
significantly from previous frames, as it would in a scene containing motion.
Note: When comparing CBR and VBR files of the same content and file size, you can make the following generalizations:
A CBR file may play back more reliably over a wider range of systems, because a fixed data rate is less demanding on a
media player and computer processor. However, a VBR file tends to have a higher image quality, because VBR tailors
the amount of compression to the image content.
Specifies the number of megabits per second of playback for the encoded file. (This setting is available only
Bitrate
if you select CBR as the Bitrate Encoding option.)
The following options appear only if you select VBR as the Bitrate Encoding option:
Specifies the number of times the encoder will analyze the clip before encoding. Multiple passes
Encoding Passes
increase the time it takes to encode the file, but generally result in more efficient compression and higher image
quality. (Adobe After Effects doesn't support multiple encoding passes.)
Specifies the number of megabits per second of playback for the encoded file.
Target Bitrate
Specifies the maximum number of megabits per second of playback you want the encoder to
Maximum Bitrate
allow.
Specifies the minimum number of megabits per second of playback you want the encoder to allow.
Minimum Bitrate
The minimum bitrate differs according to the format. For MPEG-2-DVD, the minimum bitrate must be at least
1.5 Mbps.
Compresses each frame in the source video to the fixed limit you specify, producing a file
Allows the exported file's data rate to vary within a range you specify. Because a given
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