Grass Valley Imagestore 750 v.3.0.1 User Manual
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Advanced Audio
Dolby
This module can decode both Dolby E and Dolby Digital. The Imagestore 750 decoder applica-
tion shown here is for Dolby E contribution audio only. The module accepts a stereo pair of
Dolby data and up to 8 channels of backup PCM (not shown in the left figure) plus a backup
metadata stream (not shown). The module outputs eight PCM audio channels, two PCM down-
mix audio channels (not shown) and a metadata stream. The delay through the module is 1
frame, and an appropriate video delay should be applied to compensate for this.
Fig. 6-8: Dolby CAT552 module Input/Output
Fig. 6-9: Imagestore 750 Configurator - Audio Graph representation of Dolby Decoder
Oxtel automation commands exist for controlling the module’s decoding mode. (See
The following decode modes are supported:
Automatic
Decodes any compatible input type. When Dolby data is missing, the decoder
uses backup PCM.
Dolby E
Decodes only valid Dolby E and mutes any other type.
Dolby Digital
Decodes only valid Dolby Digital (AC-3) and mutes any other type. It uses the
stream type defined.
Mute
Mutes regardless of the input type.
Force backup
Forces the use of backup audio regardless of the input type.
A metadata revision preset file can also be defined. This file is used by the decoder module
when there is no available metadata source from either the Dolby input or backup metadata
stream.
The decoder’s down-mix outputs provide an alternative stereo-only output based on the
surround output. The down-mix mode parameter may be set to Lo/Ro (default), mono, or mute.
The down-mix program select parameter indicates which program in the Dolby E bitstream is
desired for down-mix.
E
8 audio ch.
Dolby E, 2 audio ch.
1 Frame
Delay
Metadata