Audio Output; 3D Camera; Keystone Controls - PRG MBOX User Manual

Audio Output

Mbox v4 provides a preference for selecting the audio output device that Mbox will use when playing back audio.
The selected device does not have to be the same as the default audio output device selected in the System Prefs.
The default output device should be left as the "built-in" audio output in most cases, to direct system noises to the
computer's speaker, rather than to the same audio output that Mbox is using.
There is also an audio playback offset preference which allows the audio to be advanced/delayed vs. the video playback
when playing a movie. This is a global preference, affecting all audio playback on the server. Typically, this preference
will be set to a positive number, indicating that the audio is advanced with respect to the video. This is because sound
travels more slowly that light, resulting in an audio delay over longer distances. The preference has a range of -2.0
(delay) to +2.0 (advance) seconds.
Note: Mbox v4 can play eight files with audio at the same time. Files (for Mbox v4.1) can have two audio channels
(stereo). Beginning with Mbox v4.2 both movies with embedded audio and sidecar audio files will allow for playback of
up to 24 channels of audio.

3D Camera

As in previous versions of Mbox, there is a 3D camera that allows perspective views of 3D objects within Mbox's 3D
environment. Mbox Designer has a configurable/controllable 3D camera, but Mbox Studio and Mbox Mini have a default
3D camera that is not configurable.
Mbox Designer v4's 3D camera and its control parameters work differently to the camera and controls in Mbox v3.x.
In Mbox v3.x the camera was always pointing towards the center of 3D space (X,Y,Z = 0,0,0) unless the pitch or yaw
controls were changed. The v3.x camera could be orbited around the center of 3D space. While these controls were
simple, they meant that the camera could not be horizontally or vertically panned, and that the camera position, which
used 16-bit controls, couldn't be related to actual 3D coordinates.
In Mbox v4, the camera itself has an adjustable X,Y,Z position (which defaults to 0,0,10) and also has an adjustable
lookat position (which defaults to 0,0,0). This allows both the camera and its position to be adjusted, either
independently or at the same time – thereby allowing for panning. The orbit, pitch, and yaw controls have been
eliminated.
Due to the changes in the 3D camera in Mbox v4, two of the controls have non-typical defaults. The camera Z position
default is 42767, which equates to a value of 10 units in 3D space. And the camera FOV has a default value of 71, which
equates to 25°, which is the default FOV in the projection editor in Mbox Remote. These defaults allow the camera to be
seamlessly switched between DMX and Mbox Remote control without any perspective shift if the values (in both DMX
and Remote) are at their defaults.

Keystone Controls

Mbox v4 uses 16-bit controls for DMX keystone corner control – as opposed to the 8-bit controls in Mbox v3.x. Also, the
Mbox v4 keystone corners can be moved outwards as well as inwards. The DMX keystone controls also include X and Y
linearity parameters.
The DMX keystone controls include a parameter to enable/disable the controls (DMX control is disabled by default) and
this parameter has different options for the blend area curve type/mode. The new options match those found in Mbox
Remote for vignettes – linear, raised cosine, and sine. For most situations, the linear option is the most appropriate.
Each curve also has a grid option, allowing a grid to be overlaid onto the output image. Finally, there is an option to have
the DMX keystone enabled but to disable the blending and turn on the grid without the blending.
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