Dolby Laboratories Multichannel Audio Tool DP570 - Manual (Page 46)

30 Dolby ® DP570 Multichannel Audio Tool User’s Manual
Using the DP570 Features
Figure 4‐6
Figure 4-5 Short-term Measurements
Since the short‐term measurement considers only the previous 10 seconds of program
material, the measured value can be much more dynamic than the measured value in
Infinite mode.
The benefit of short‐term measurement is that it allows the operator to see short‐term
variations in loudness level within a program. Many skilled audio operators prefer to use
the short‐term measurement, as they find the information on near‐term dynamics to be
very useful when mixing or producing a program. These operators are capable of
managing overall program loudness by continuously reading and interpreting the
short‐term measure
2 .
Table 4‐2 lists several example applications for both measurement modes.
Note: In programming that includes heavy dynamics processing, and therefore a smaller
dynamic range, the short‐term measurement may not be considerably more
dynamic than the infinite.
2 We do not recommend averaging multiple short‐term measurements, either arithmetically or by
summing the anti‐logs, to come up with a long‐term average, since each of the short‐term measurement
values is valid only for the previous 10‐second period. Consider a situation where the operator takes a
60‐second measurement in Short‐term mode. The measurement value displayed at the end of the period
represents only the time interval from second 50 to second 60, not the entire minute. Instead, use Infinite
term measurement and the Pause function.
Table 4-2 Measurement Mode Applications
Short-term Infinite
Live broadcast event Program ingest
Postproduction and/or mixing with
audio engineer Postproduction to check conformance with
delivery requirements, including dialogue
normalization value
Quality control: measuring short‐term
program dynamics Quality control: measuring overall program
for normalization and/or dialogue
normalization provisioning purposes
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