Apple Compressor 2 - Manual (Page 150)

150 Chapter 10 Creating MPEG-2 Output Files
4 Decide whether you want the GOP pattern to be open or closed and click the
appropriate button.
Note: For all HD MPEG-2 formats, the GOP structures are closed.
See “ Understanding GOPs and Frame Types ” on page 140, “ Things to Consider When
Choosing a GOP Setting ” on page 140, or “ GOP Tab ” on page 138 for more information
about GOPs.
Step 4: Choose Extras settings
You can control the inclusion or exclusion of specific MPEG-2 authoring information in
the Extras tab.
1 Click the Extras button in the MPEG-2 Encoder pane to open the Extras tab.
Working With MPEG-2 I-Frames
The Compressor Preview window offers additional MPEG-2 transcoding flexibility by
allowing you to manually insert I-frames into your output MPEG-2 file at any frame
location, regardless of your chosen GOP pattern and size. These are known as forced
I-frames, and may be useful for improving the quality of the MPEG-2 file in the vicinity
of the scene change. See “
Understanding GOPs and Frame Types ” on page 140 for
more information on I-frames.
In addition, adding I-frames to your clip allows you to create chapter markers that
DVD Studio Pro can understand and use. See “
Adding Markers to a Clip ” on
page 220 and “ Adding DVD Studio Pro Chapter Markers to a Clip ” on page 222
for more information.