User guide

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Chapter 8, Defining Your Adobe Premiere Pro Settings
$ MPEG-2 IBP Renders video to MPEG-2 IBP format.
2 Under Data Rate (Mb/sec), you can select the encoding type and data rate
for the MPEG-2 compression.
$ Encoding type From this list, select one of the following:
• Constant bit rate (CBR) Video is compressed at your selected target
data rate, which is useful when you need to limit or predict the size of
your .mxf file. However, if your video is very complex (such as scenes
with many colors or sharp edges), you’ll need to select a high data rate
to avoid having frames of very blocky video in your file.
• Variable bit rate (VBR) Video is compressed at varying data rates
based on the complexity of the video. The target data rate you select is
used as the average data rate for the compression.
$ Min, Ta r g et , and Max sliders Use these sliders to select your desired data
rate. The higher the target data rate you select, the better the video quality
will be. Only the
Tar ge t slider will be available if you selected Constant
bit rate (CBR)
. If you selected Variable bit rate (VBR), all three sliders
will be available so that you can set the minimum, target, and maximum
data rates for the video compression.
¦NoteThe maximum target data rate varies for SD and HD video and
depends on your selected encoding type and MPEG-2 profile (see below).
3 Under GOP Structure, you can customize the GOP structure for the
MPEG-2 IBP compression as follows:
$ GOP length Determines the number of frames in the GOP (Group of
Pictures).
$ Subgroup length Determines the subgroup length of B-frames and
P-frames in the GOP, after the initial I-frame. For example, a subgroup of
3 appears as “BBP,” and a subgroup of 2 appears as “BP.” The available
subgroup lengths depend on your selected GOP length.
4 Under Profile, select one of the following MPEG-2 profiles:
$ 4:2:0 This profile uses 4:2:0 luminance/chrominance sampling and is
suitable for broadcast transmission and distribution on DVD.
$ 4:2:2 This profile uses 4:2:2 luminance/chrominance sampling and is
suitable for high-quality distribution and archiving.
5 Under Motion Estimation, drag the slider to adjust the quality of the
motion estimation used for the video compression. The default setting gives
good results for most video. However, if you have a lot of fast motion in your
video, such as fast-paced sports footage, you can get better results by
dragging the slider to the right (towards
Slow/High quality). This improves
the quality of the motion estimation, but decreases the speed of the video
compression. Alternately, if you have mostly slow-paced video, you may
Axio Installation and User Guide.book Page 118 Monday, July 14, 2008 8:00 AM