Grass Valley AMX-3981 2014 - Manual (Page 80)

GUIDE TO INSTALLATION AND OPERATION
74 | AMX-3981
6.2 Dolby Digital and Dolby Digital Plus encoder
• Identified as MOD-DOLBY-ENC-D-2 on the module tab.
The Dolby Digital Plus functionality is available in
module version 5.1.0.0 and higher (version number
shown in the upper right corner of the tab).
6.2.1 Shuffler Inputs
An input shuffler allows any combination of the input
channels (default are CH1 to CH6). The input labeling will
follow the Metadata (Coding Mode parameter for the
selected Program).
• Pulldowns: Available input channels 1 to 32
The graphic shows the output channels in use.
Output Channels
Use the pulldown to select the pair of channels on which the
encoded output will be placed.
[1-2, 9-10, 17-18, 25-26]
Dolby Digital Plus
Select the checkbox to activate Dolby Digital Plus encoding
instead of Dolby Digital. Available in module version 5.1.0.0
and higher.
6.2.2 Configuration
Encoder Control
Use the pulldown to select the operational mode: Dolby Digital Encode or Dolby Digital Plus Encode (as selected
using the Dolby Digital Plus checkbox) or Pass-through.
Test signals at -18, -20 dBFS and silence are available for each mode.
• Encode test modes will generate a test bit-stream containing a 1 kHz sine wave for full bandwidth channels and
100 Hz for the LFE channel of a 5.1 program.
• In Pass-through test modes, it will generate a 1 kHz PCM sine wave at its outputs.
When the encoding mode changes, the output mutes and
resumes in the selected mode within one second.
Data Rate
The card can encode at all Dolby Digital data
rates between 56 kbps and 640 kbps and all
Dolby Digital Plus data rates between 32 kbps
and 1024 kbps, although there are constraints in
regards to data rate versus channel configuration
(audio coding mode) – see Table 1.
It supports automatic switching of the data rate
based on the Coding Mode.
Table 1: Auto Data Rate Assignment
Coding
Mode
Dolby Digital
Automatic 384 Dolby Digital
Automatic 448 Dolby Digital
Plus Automatic
1/0 96 kbps 96 kbps 64 kbps
2/0 192 kbps 256 kbps 128 kbps
2/1, 3/0 256 kbps 256 kbps 160 kbps
2/2, 3/1 320 kbps 320 kbps 192 kbps
3/2 384 kbps 448 kbps 192 kbps
Figure 6.5 Audio Module - Dolby Digital and Dolby
Digital Plus Encoder