Apple has released Pro Applications Update 2008-03, addressing issues in which clusters were not visible in Compressor and Batch Monitor, and Compressor services did not appear in the Apple Qmaster pane of System Preferences. The download is free, and the package weighs in at 64.4 MB.

From Apple's Support section,

About Pro Applications Update 2008-03

Pro Applications Updates improve reliability for Apple's professional applications and are recommended for all users of Final Cut Studio, Final Cut Server, and Logic Studio.

Pro Applications Update 2008-03 addresses general performance issues and improves overall stability.

The Cupertino-based Mac maker points out that Pro Applications Update 2008-03 includes Compressor 3.0.4 and Apple Qmaster 3.0.4. Noting that the issues spawning missing clusters, as well as the service issues having been resolved, Apple claims Compressor 3.0.4 and Apple Qmaster 3.0.4, together with the Mac OS X v10.5.5 update, resolve an issue in which clusters were not visible in Compressor and Batch Monitor, and Compressor services did not appear in the Apple Qmaster pane of System Preferences. Final Cut Studio users can also head over to Apple's Support section where the release notes for Compressor 3 are listed in their entirely.

Previous updates to Compressor added options to create media files for Apple TV with anamorphic (non-square) pixel aspect ratios. The pixels are scaled by Apple TV to fit the intended aspect ratio during playback. In Compressor 3.0.3, an additional item appeared in the Device pop-up menu of the H.264 for Apple Devices Encoder pane - Apple TV SD (Anamorphic). Since then, users can choose this option to create an output media file with an anamorphic (non-square) pixel aspect ratio. The choice they make in the Device pop-up menu is reflected in the set of possible options in the subsequent Aspect Ratio pop-up menu.