syndrome3D: TechNote #001

This technote is a list of the issues and problems in MacOS X applications that are known to be caused by the lack of an audio output device. These problems do not normally manifest on most Mac models, since they have a built in audio device which is always available. The G4 Cube is the primary exception, since it has no built in audio and depends on USB audio to provide an audio output device. If the external USB speakers (or another USB audio product) are not connected to the Cube, some applications and processes that rely on the existence of a sound output device will fail. Based on the information available in the Apple Hardware Developer's Note for the Xserve, it is most likely affected by this issue as well, unless Apple has already patched this for the Xserve model at the OS level. I do not have access to an Xserve to confirm this, however.

All of the issues listed have been confirmed to be solved by the VirtualSpeaker kernel extension, which creates a virtual audio output device which is selected by default when no other audio device is available.

iMovie 2.x, 3.0.x -- capturing video from a DV source
When attempting to capture video, the video will not display properly in the video/preview window, showing a blue screen with the message camera connected or sometimes only a black image. Any attempt to view or record the DV video stream will result in a seemingly endless number of empty (0k and <1k) files being produced in the current project folder.
Similar behavior has also been noted in BTV, however it can be fixed by deselecting the "Use Sound" setting in that application's general preferences. It is likely that these video capture problems occur in any application that attempts to capture DV video (Final Cut Pro, etc...) however I don't have access to other applications to confirm it.

DVD Studio Pro 1.5.x -- previewing a DVD project or menu
If you attempt to preview a DVD project or DVD menu, the DVD Studio Pro application will crash, even if there are no sound related assets included in the current project.

Quicktime Player 5.x, 6.x, Pro -- alert when opening movie
When opening any quicktime movie with a sound track, an error message will be displayed: "You may experience problems playing a soundtrack in ... because a software component needed by the movie could not be opened. Would you like to close the movie or continue?". The video will play properly if the user chooses to continue. This issue seems to affect any movie format that includes an audio track or a mixed audio/video track.

Games using the Carbon SoundManager API -- some programs crash or quit at launch
This issue affects a variety of games and sound-using applications (including commercial games), which show error dialogs or quit unexpectedly when launched or when the first sound attempts to play. This is due to the fact that the Carbon SoundManager API returns an error to the application when it tries to open a sound channel with no sound output device present (which is probably the proper behavior, but maybe not the best), and either the program's error handling decides to quit gracefully when the error is recieved or the program doesn't check for errors and then crashes when it tries to use the non-existent sound channel. Some programs do handle the error and run properly by choosing not to use any audio. A few others can be fixed by manually editing the games preference file to shut off sound (although most seem to try to initialize a sound channel during launch regardless of whether it will be used and crash anyway).

This technote will be updated with information regarding additional applications once the reported issues in those applications have been confirmed to be caused by the lack of an audio output.