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Jon Chappell

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Using Compressor with multiple cores

Here's a quick tip that a lot of people still don't know about. So you've just bought that shiny new Mac Pro, you finish your Final Cut Project, export to Compressor and wait.... and wait... and wait. Hang on a second, that brand-new 8-core machine is only utilizing one core!

Welcome to the world of Final Cut Studio 2, which is completely unaware of multiple cores in your system. Hopefully this will change in FCS 3 but in the meantime, here is a trick to using those cores in Compressor.

1. Go to System Preferences and open the Apple Qmaster section.

2. In the Setup tab, click Stop Sharing if Qmaster is already activated.

2. Select QuickCluster if it is not already selected.

3. Under Services, select the service marked Compressor and select the checkboxes for Share and Managed.

3. Then click Options for Selected Service.

4. Select half of the number of cores in your machine i.e. 2 for a 4-core and 4 for an 8-core (this particular machine has only 2) and click Ok.

5. If you are using Shake. Maya or have any other command-line renderer set up with Qmaster, select the Rendering item in the list and click Options for Selected Service.

6. Click the + button and add half as many Local machines as you have cores i.e. 2 for a 4-core and 4 for an 8-core, then click Ok.

7. Under the QuickCluster section, type a name for your new virtual cluster.

7. Click Start Sharing and close System Preferences.

8. In Final Cut Pro, export your sequence as a QuickTime movie. This is important. Do not choose File > Export > Compressor, as this will fail.

9. In Compressor, import the movie, set up your batch and click Submit.

10. Instead of "This machine", select the name of your new cluster in the Cluster list and click Submit. The movie clip will be processed by multiple cores in your machine.

This is called Virtual Clustering, and it is achieved by launching a new version of Compressor for every instance. This is much easier from the perspective of Compressor's programmers but it takes up more memory and is less efficient than if they were to implement true multi-core capabilities into the application.

So be aware that using this method will require considerably more memory than rendering on a single instance. Apple recommends in most cases one process for every two cores, although it all depends on the type of media you are working with and how much memory you have. If you set too many instances and don't have enough memory, your machine would slow down (or worse, crash) thus undoing the whole point of setting up the virtual clusters in the first place. Apple recommends 1 GB RAM per service but again, this depends on the media you are transcoding to.

Categories: Apple, Software, Final Cut Studio
Post ID: 332Posted Friday November 14 2008 7:04 AM

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