PRG Mbox Designer Manual 3.9 - Manual (Page 168)

160 MBOX ® MEDIA SERVER USER MANUAL
of either file (especially the movie file) once the two have been separated. (You can always shorten the movie or play
portions of it by adjusting the in and out points.)
AIFF audio files for playback on Mbox must be encoded as 2-channel (Stereo: L & R), LPCM, 16-bit Integer (Big or
Little Endian) at a sample rate of 44.1 kHz. Other sample rates will play, but will not play at the correct speed. Mbox
cannot play more than one AIFF audio file at a time. The most recent file requested will play. There is a slight
crossfade between tracks that play back, but this is only there to eliminate any pops or clicks when the audio
switches files. On the other hand, if you choose to play the audio that is embedded in movies (refer to
"Audio" on
page 106 for further info) you can play more than one audio track at a time. However, this can get "messy" since there
is no crossfade or volume control when playing embedded audio.
The audio volume control channel on the Master fixture can be used to modify the volume of AIFF audio file playback.
However, at present time the volume control does not affect embedded audio tracks in movies that use a non-
preferred codec.
Discrete Audio Support for Multichannel Audio
FireWire devices require audio outputs to be assigned to channels called "discrete - 0" through "discrete - 31." Most
QuickTime movies are made with mono, stereo, or 5.1/7.1 audio and the audio tracks and/or channels must be
manually re-assigned to work properly with the FireWire interfaces. To simply this, Mbox has the ability to
automatically take audio tracks in movies and re-assign their output to the discrete channels used by FireWire audio
interface boxes (e.g., MOTU, Fireface, RME).
With the Discrete Audio preference enabled, Mbox will automatically re-assign audio channels (sequentially) to the
discrete range if it encounters a movie with more than one audio track or a track with more than two channels. This
means that movies with a single mono or stereo track will not be affected, but since the mono output is always
assigned to discrete - 0, and stereo L & R to discrete 0 & 1, this is not an issue.
To enable discrete audio support:
Step 1. Use Mbox Remote application to enable the
preference named "Audio Discrete Mapping."
(Refer to the Mbox Remote User manual for
more information.)
Step 2. Restart Mbox Designer software.