Dolby Laboratories DP569 User Manual

Page of 90
Model DP569 User’s Manual 
Metadata 
A–5 
When received at the consumer’s Dolby Digital decoder, this parameter setting 
determines the level shift in the decoder that sets, or normalizes, the average audio 
output of the decoder to a preset level. This aids in matching audio volume between 
program sources. 
The proper setting of the dialogue level parameter enables the Dynamic Range Control 
profiles chosen by the content producer to work as intended in less-than-optimal 
listening environments, and is essential in any content production, whether it is for 
transmission in a broadcast stream or for direct distribution to consumers, as in DVDs. 
In broadcast transmission, standard setting of dialogue level ensures that the 
consumer can switch channels or watch a television program without having to adjust 
the volume control during commercial breaks. Using that standard for all content, 
whether conveyed by broadcast television, DVD, or other media, enables the 
consumer to switch between sources and programs while maintaining a comfortable 
listening level.  
Note:   Programs without dialogue, such as an all-music program, still require a careful 
setting of the dialogue level parameter. When setting the parameter for such 
content, it is useful to compare the program to the level of other programs. The 
goal is to allow the consumer to switch to your program without having to 
adjust the volume control. 
The Scale 
The scale used in the dialogue level setting is from –1 to –31 dBFSLeqA in 1 dB steps. 
Contrary to what you might assume at first, a setting of –31 represents no level shift in 
the consumer’s decoder, and –1 represents the maximum level shift. Here’s why: 
Dolby Digital consumer decoders standardize the average loudness (averaged over 
time by the formula LeqA) to –31 dBFS (31 dB below 0 dB full-scale digital output) 
by applying a shift in level based on the dialogue level parameter setting. When a 
decoder receives an input signal with a dialogue level setting of –31, it applies no 
level shift to the signal because this indicates to the decoder that the signal already 
matches the target level and therefore requires no shift. In contrast, a louder program 
requires a shift to match the –31 dB standard. When the dialogue level parameter 
setting is –21, the decoder applies a 10 dB level shift to the signal. When the setting is 
–11, it applies a 20 dB level shift, and so on. 
A Simple Rule: 
31 + (dialogue level value) = Shift applied 
Example: 
31 + (–21) = 10 dB