FCPX currently doesn't export markers to Compressor... super lame! This app converts markers from a .fcpxml file to a .txt file that can be imported into compressor.
In the Final Cut Pro X project browser, highlight a project and select "File" => "Export XML".
Option 1 - Open Markers.app. Select your .fcpxml file. Save your markers text file
Option 2 - Drag your .fcpxml file onto the Markers.app icon. You'll be asked where to save the markers text file.
Some users experience a slight timing error when importing markers into compressor - especially when converting very long projects. If your markers are slightly off, select "Yes" to the dialog.
In the Compressor preview window, click the marker button and select "Import Chapter Marker List". Select your markers text file, and BOOM! Markers imported.
Due to an issue with the way FCPX deals with unused clips, It's recommended that you create your markers as the final step in your workflow. Not doing so can result in markers being duplicated.
This app finds all markers within the entire project, even those within compound clips.
Please post any issues - better yet, send a pull request!