Grass Valley DAP-1781 - Manual (Page 36)

GUIDE TO INSTALLATION AND OPERATION
36 | DAP-1781
4.3.3 Dolby Digital (AC-3) Encoder tab
4.3.3.1 Inputs and Outputs
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).
The Dolby-Digital signal is mapped into the channel
pair selected in the pull-down “Output Channels”.
4.3.3.2 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).
It supports automatic switching of the data rate based on the Channel Mode.
Table 1: Auto Data Rate Assignment
Channel Configuration 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
Stream Number
Sets the output stream number from 0 to 6.
Bit-stream 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 Program used for encoding, refer to Metadata tab to access settings.
Reversion Mode
The source of the Metadata used for encoding is specified in the Metadata tab. This parameter specifies the
response of the module when this Metadata bit stream is lost or corrupted.