Model DP569 User’s Manual Applications
3-3
MUXDP569
Main
Out
L/R
Digital
In
Multiplexer
Dolby
Digital Input
GPI
Input
GPI
Status
Alarms and
Status
MPEG Transport
stream output
DP572
Video Ref (Studio
Ref or Source VTR)
Main
Input Digital
Audio
Outputs
Dolby E
Metadata
Out
Aux
Input
GPI Status
Figure 3-2 Connection Between a DP569 and DP572
3.1.3 Metadata Reversion
It is important to consider what will happen in situations where metadata does not
exist. There are two common situations where metadata may not be available.
1. When using audio material that has been supplied without metadata—for
example, archived material or regular stereo broadcast programming such as
news or local programming material.
2. Equipment failure within the broadcast audio chain.
When a DP569 (or Dolby E products) does not receive metadata, it will revert to a set
of preconfigured metadata parameters. This reversion behavior can be used as part of
a systems design to apply the correct metadata values in case 1 above as well as
providing suitable values in case 2. See Section 4.2.2.
We suggest you contact your systems designer or Dolby Laboratories to discuss the
correct settings for your installation and operating practices.
3.1.4 Coding Delay and Audio/Video Synchronization
It is important to establish the correct system timing relationship between the video
encoder or MPEG transport stream multiplexer and the DP569 in order to maintain
sync. In most cases the MPEG encoder/multiplexer will be able to compensate
internally for the DP569 encoding delay and will have a setting to enable this.
If possible, it is recommended that both the MPEG encoder/multiplexer and the
DP569 be set to compensate for 200 ms of delay (plus an additional one frame in the
multiplexer if also compensating for the decoding delay of Dolby E). As 200 ms is
larger than the minimum delay value required by the DP569 (at 48 kHz) small timing
adjustments can be made in the DP569 if necessary.