Apple Compressor (4.0) - Manual (Page 47)

Chapter 4 Assign settings and preview media 47
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Compression markers: Compression markers are also known as manual compression markers.
These are markers you can add in the Compressor Preview window to indicate when
Compressor should generate an MPEG I-frame during compression. For more information
about I-frames, see
About GOPs (groups of pictures) on page 99.
These markers appear as blue in the Preview window timeline.
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Edit/cut markers: Edit/cut markers are also known as automatic compression markers. These
markers are intended to be at each cut or transition point in a sequence. During transcoding,
Compressor uses edit/cut markers to generate MPEG I-frames at these points, improving
compression quality.
These markers appear as green in the Preview window timeline.
Markers are supported in the following output file formats:
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MPEG-2
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MPEG-4 when configured for podcasting (audio-only with the Enhanced Podcast checkbox
selected)
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QuickTime Movie
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H.264 for Apple Devices
Important: You can set and configure markers for other output file formats, but they are not
included in the encoded output file.
Manually add and remove markers
The Preview window includes comprehensive marker support, including the ability to manage
markers already added to the source media file, manually add or remove markers, and import
chapter marker lists. When you add a marker to a clip, it appears as a chapter marker by default.
You can then change the marker to a compression or podcast marker if you wish (see
Add
compression or podcast markers on page 49).
Add a chapter marker to your clip
1 In the Preview window, choose Show Chapter/Podcast Markers from the Marker pop-up menu,
so that there’s a checkmark by it.
2 Choose a clip from the Batch Item pop-up menu or click the Batch Item selection button until
the clip you want appears in the pop-up menu.