GUIDE TO INSTALLATION AND OPERATION
XVP-3901 |
113
6.2 Dolby Digital (AC-3) encoder
•
Identified as MOD-DOLBY-ENC-D-2 on the module
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
This encoder places the output on channels 17 and 18.
6.2.2 Configuration
Encoder Control
The operational mode can be
Dolby Digital Encode
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, 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
.
Stream Number
Sets the output stream number from 0 to 6.
Bitstream Format
The output mode of the Dolby Digital bit-stream can be set to 32-bit, 16-bit Channel 1 or 16-bit channel 2. The default
setting is 32-bit.
Metadata Source
Selects the Metadata Path (Path 1 or 2) used for encoding. Refer to
Dolby Metadata tab
to access settings.
[Path 1, Path 2]
Table 1: Auto Data Rate Assignment
Coding Mode Automatic 384 Automatic 448
1/0
96 kbps
96 kbps
1+1
192 kbps
192 kbps
2/0
192 kbps
256 kbps
2/1, 3/0
256 kbps
256 kbps
2/2, 3/1
320 kbps
320 kbps
3/2
384 kbps
448 kbps
Figure 6.5 Audio Module - Dolby Digital Encoder