4.1.2

Chapter 4 Advanced adjustments 43
Video properties
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Frame size: Use the pop-up menu to set the frame size (resolution) for the output le.
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Pixel aspect ratio: Use the pop-up menu to set the pixel aspect ratio (the ratio between the
image frame width and height). You can also modify the aspect ratio of the output le using
cropping and padding properties. For more information, see Modify frame size overview on
page 67.
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Frame rate: Use this pop-up menu to set the playback rate (the number of images displayed
per second) for the output le. For more information, see Frame rate options overview on
page 69.
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Field order: Use the pop-up menu to set the output scanning method (either the eld
dominance or a conversion to progressive scanning). There are four options:
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Same as Source: Maintains the same scanning method used by the source media le.
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Progressive: Scans complete frames (not frames divided into interlaced elds).
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Top First: Scans interlaced elds, giving dominance (eld order) to the top eld, also known
as eld two, the upper eld, or the odd eld.
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Bottom First: Scans interlaced elds, giving dominance (eld order) to the bottom eld, also
known as eld one, the lower eld, or the even eld.
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H.264 prole: Use the pop-up menu to set the video compression for the output le. There are
three options:
•
High: Provides high quality output.
Note: This setting is not compatible with older MPEG-4 Part 10 devices.
•
Main: Similar to the Baseline prole, with additional support for standard-denition (SD)
video requirements.
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Baseline: Primarily for video conferencing and mobile applications.
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Entropy mode: Use the pop-up menu to set the entropy mode to CABAC, which provides
higher-quality output, or CAVLC, which is faster.
•
Key frame interval: Enter a value in the text eld to set the key frame interval (number of
frames) at which you want key frames created in your output le. Alternatively, you can select
Automatic to have Compressor choose the key frame interval rate (the displayed value is 0
with Automatic on; the actual value is determined during the encoding process).
•
Data rate: Sets the number of kilobits per second (kbps) required to deliver your video le.
Drag the slider or enter a value in the eld. This setting is useful if you have a specic bit rate
(such as a DSL connection) or amount of space (on a DVD or CD- ROM).
Important: When you set a data rate, you override other codec quality properties because the
codec compresses the le as much as it needs to based on its data rate limit.
•
Multi-pass: Select this checkbox to turn on multi-pass encoding that uses additional analysis
of video frames to produce a high-quality output le. For faster (single-pass) transcoding, turn
this feature o by deselecting the checkbox.
•
Allow frame reordering: Select this checkbox to potentially provide a better-quality output le
by allowing Compressor to reorder video frames during transcoding.
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