Apple Compressor 3 - Manual (Page 218)

4 Decide whether you want the GOP pattern to be open or closed and click the appropriate
button.
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 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 and Adding
Chapter or Podcast Markers to a Clip for more information.
See Understanding GOPs and Frame Types , Things to Consider When Choosing a GOP
Setting , More About GOPs and Markers , and GOP Tab for more information about GOPs.
Stage 4: Choosing Extras Settings
You can control the inclusion or exclusion of specific MPEG-2 authoring information in
the Extras tab.
To open the Extras tab and choose Extras settings
1 Click the Extras button in the MPEG-2 Encoder pane to open the Extras tab.
2 Select the “Add DVD Studio Pro metadata” checkbox if you want Compressor to parse
specific MPEG-2 authoring information rather than parse the information later in
DVD Studio Pro.
Important: Selecting this checkbox may make your MPEG-2 files incompatible with any
DVD authoring tools other than DVD Studio Pro 2 (or later).
3 Select the “Include chapter markers only” checkbox if you want to exclude automatic
compression markers from the stream but still retain the chapter markers.
218 Chapter 18 Creating MPEG-2 Output Files