Instruction manual

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2. AJA Control Panel
By “Master”, we mean a process that can control and change what the Io HD is
doing and the Primary and Secondary formats that it uses (as set in the Control
Panel “Formats” tab screen).
QuickTime Application—1st Priority
If a running QuickTime application uses Io HD for capture or output, it controls
the Primary format via its own menus and settings. For example, when Final Cut
Pro is active (it’s the topmost application) and has Io HD as its “A/V Device”, then
the Io HD's Primary format is determined by Final Cut's “Video Playback”
submenu (under the “View” menu) or in its “Audio/Video Settings...” dialog under
A/V Devices.
When a QuickTime application is in control of the Io HD—versus one of the other
masters—it will be indicated by a label in both the AJA Control Panel's Formats and
Control tabs. The AJA Control Panel’s Primary Format menu will also indicate that
it is not active while the QuickTime application is running—it will be grayed-out.
What can be confusing is that QuickTime applications can start and stop and
change modes—even while they are running! And the behavior of different
QuickTime applications can vary: some applications take control of the Io HD as
soon as they are launched and don't give it up until they quit, while other
applications take control of the Io HD only when they are the “front-most” running
application and then relinquish control when they’re not. Final Cut Pro is one of the
latter type QuickTime applications. This difference in behavior can surprise you
when you click in and out of multiple QuickTime application windows.
To illustrate such possible confusion, consider this multiple application scenario:
1. Open Final Cut Pro, select Io HD as the A/V device. FCP takes control of the
Io HD and tells it what Primary format to use. If one of the FCP windows
covers up the AJA Control Panel application (which typically happens), you
won't be able to see the “Io HD is in use by Final Cut Pro” message displayed
in the Control Panel, or be able to tell which format FCP has selected. (This
is why we recommend you arrange your display so you can see the Control
Panel at all times.)
2. Next, you want to see what the Io HD is doing, so you find the Control Panel
application by clicking around on the desktop, eventually clicking on the
Control Panel to make it visible. As soon as FCP realizes it is now running in
the background, it gives up control of the Io HD board. The Control Panel
application takes away the “...Final Cut Pro” message.
3. With the Control Panel the topmost application—and in control of the
board—you now switch to a different Primary format.
4. However, when you click back on Final Cut Pro and bring it back to continue
your project, it becomes the master again and resets the board's Primary
format to the one determined by Final Cut’s A/V Settings dialog. To further
the surprise, if FCP's windows are covering the AJA Control Panel window,
the change will be hidden and you won’t know why the board isn't doing
what you told it earlier via the Control Panel.