Grass Valley DAP-1781 - Manual (Page 32)

GUIDE TO INSTALLATION AND OPERATION
32 | DAP-1781
4.3 Dolby
This window provides control and status information
for an optional Dolby module. The active tab
depends on the type of the optional card physically
installed on the DAP-1781.
4.3.1 Dolby Decoder tab
The decoder supports a Dolby-E, Dolby Digital or
PCM signal; any other non-PCM signal will be lost
through the decoder module, its outputs will be
muted.
For a Dolby-E input signal, the associated Metadata
bit stream may be output to the video card (via A-
BUS) and to the rear Metadata Out connector.
(Refer to the Metadata tab, 4.4)
When a PCM signal is fed to the decoder input, the
selected Metadata Backup input will be selected as
Metadata source.
(Refer to the Metadata tab, 4.4)
A selector is provided at the Decoder input. As soon
as the Bit Stream Detection Mode in On, the
output channels of the Decoder are always routed
to the internal channels 9 to 16 of the DAP-1781,
with a mapping related to the input format. The
unused channels will be muted.
4.3.1.1 Control sub-tab:
The Bit Stream Detection Mode dictates the action
taken by the decoder for each type of input bit stream.
In Auto mode, the decoder automatically
recognizes and decodes PCM, Dolby Digital or
Dolby-E input bit streams. If Dolby-E only is
selected, the decoder recognizes and decodes only
this type of bit stream, otherwise the decoder
outputs are muted. The same applies for the Dolby
Digital only selection. If Mute (OFF) is selected, all
outputs are muted for any type of input, the Mute
mode disables the Dolby decoder.
The Input Selection determines the Dolby decoder input channel pair. Channels 1 to 8 represent the AES1
to AES4 digital inputs. When a video card is present, eight extracted audio channels are available as channel
9 to channel 16. See Audio Processing/Config tab for the input selection from the video card.
The Delay Compensation tab allows frame adjustment of the audio decoder outputs versus video delay, the
default value is minus one frame for the Dolby Decoder module. The frame length is related to the reference
input frame rate. When the DAP-1781 is referenced to its AES 1 input, or is free-running, the default frame
length is defined in the Reference tab.
The Decoder Status section indicates the bit stream format detected at the decoder input. The possible
values are: PCM, Dolby-E (16, 20 or 24 bits), Dolby Digital (16 or 32 bits, Channel 1, 2 or both). The detected
Dolby format will give access to the corresponding tab.