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Table Of Contents
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Chapter 17 Export
GOP Structure Samples
With different settings for GOP type, N and M values, a wide range of GOP structures is possible:
Minimum Base Quantization
This parameter influences encoding quality and ranges between 1 and 20 (theoretically it can go up to
112, but that would generate inacceptable results). I, B and F slider move in sync. 1 specifies the optimum
quality, 20 is not so good, but still ok.
Default = 2 (IPB Capture = 1).
One exception: IPB Settings when accessed via the Logging Tool (not in all products) let you move the
three sliders individually.
Additional Options
Detect scene change -
This is a function of the Logging Tool. On detecting subsequent video images which differ greatly
from one another, Avid Liquid acknowledges the new scene by inserting an I-Frame at the start of
the new scene.
4:2:2 -
is a color sampling procedure (Chroma Sampling; see also the Glossary for more information on
various sampling methods). DV and also DVD conforming to MP@ML employs a 4:2:0 sam-
pling, which is the default for all MPEG related data export. When (S)VCD or DVD is selected as
the Destination format, the 4:2:2 option remains inaccessible. 4:2:2 is not in line with DVD specs.
4:2:2 generates a better quality output for use in professional post production facilities. Valid
Destinations are Elementary and Program Stream exclusively, at bit rates up to 50 Mbit/s.
GOP Size GOP Type (N) RefPicture
Period (M)
IPB Structure
13 Closed 3 I
PBBPBBPBBPBBIPBB...
12 Closed 3 I
PBBPBBPBBPBIPBB...
12 Open 3 I
BBPBBPBBPBBIBB...
1 Closed 1 IIIII
...
2Closed1I
PIP. . .
4Closed1I
PPPIP.. .
2Open2I
BIBIB...