User guide

Viz Engine Administrator’s Guide
Copyright © 2014 Vizrt Page 123
and holds one second of data and this is the maximum delay that can be achieved with
the described mechanism.
The SyncTargetPosition (set in SECTION AUDIO_CONFIG) defines the position (relative
to the play out position of the Matrox or Targa board) where the audio data for the
direct sound cards are branched. If the card is running slower than the reference card,
the synchronized position will move away from the play out position. If it is faster, the
SyncTargetPosition will move to the playout position. The SyncTargetWindowSize (set
in SECTION AUDIO_CONFIG) defines the border, when Viz Engine starts to resample the
direct sound data to bring the SyncTargetPosition back in place. The predefined value
of 250 samples is a good compromise between performance and quality. If a cheap
audio card is used, and small artifacts can be heard, try to increase this value. Good
ranges are 250 up to 600.
The SyncTargetPosition is used to synchronize the different audio cards to each
other. Every audio card shows a specific delay behavior. Increase or decrease this
value if one card is faster than the other. If the value is too small artifacts will occur;
however, most audio cards work fine with the predefined values. SyncTargetPosition
and SyncTargetWindowsSize (set in SECTION AUDIO_CONFIG) are configurable settings
that can be set separately for every activated audio card.
This section also contains information on the following topics:
• Channel Device and Channel Track settings
7.3.1 Channel Device and Channel Track settings
In Viz Engine it is possible to combine two or more devices for playout of the Viz
Engine’s internal audio channels.
Note that Viz Engine internally can use up to 16 channels. On many professional
multichannel cards the channels are organized in virtual devices with 2 channels. A
good example is the following configuration:
Available2 = M-Audio Delta 66 1+2
Available3 = M-Audio Delta 66 3+4
In Viz Engine it is possible to combine these two devices and create a quad speaker
configuration as shown below.
VIZChannelDevice0 = M-Audio Delta 66 1+2
VIZChannelDevice1 = M-Audio Delta 66 1+2
VIZChannelDevice2 = M-Audio Delta 66 3+4
VIZChannelDevice3 = M-Audio Delta 66 3+4
VIZChannelDevice4 = Realtek HD Audio output
VIZChannelDevice5 = Realtek HD Audio output
VIZChannelDevice6 = Realtek HD Audio output
VIZChannelDevice7 = Realtek HD Audio output
VIZChannelDevice8 = none
VIZChannelDevice9 = none
VIZChannelDevice10 = none
VIZChannelDevice11 = none
VIZChannelDevice12 = none
VIZChannelDevice13 = none
VIZChannelDevice14 = none
VIZChannelDevice15 = none
VIZChannelTrack0 = 0
VIZChannelTrack1 = 1