Dolby Laboratories Multichannel Audio Tool DP570 - Manual (Page 45)

Measuring and Setting the Dialogue Level
Dolby ® DP570 Multichannel Audio Tool User’s Manual 29
value within Dolby E and Dolby Digital bitstreams. The DP570 measurement feature will
yield best results when the operator measures portions of the program that contain only
minimal nondialogue material.
Using Infinite Measurements
Infinite measurement mode conforms to the specifications of ITU‐R Rec. BS.1770. In this
mode, the calculated value is the long‐term level, integrated over the entire period since the
measurement was last reset.
Infinite mode is typically used to measure the entire duration of the program, or several
long sections of a program, to find the long‐term level. Since Dialogue Intelligence
™ is
available only in the Dolby LM100 Broadcast Loudness Meter, we suggest using the
following steps to obtain an estimated value for the entire program:
1. Review the program, noting the locations of several representative sections where
dialogue is present.
2. Cue the beginning of the first selected segment.
3. Click Reset to clear past measurements.
4. Measure the first segment, then click Pause to pause measurement.
5. Cue the second segment.
6. Click Pause again to resume measurement.
7. Continue in this fashion, pausing measurement between selected segments until the
program is completed.
This process allows you to accurately estimate the average level of all of the individual
dialogue sections.
1
The term representative section indicates a shorter section of the program being measured
that contains spoken dialogue levels that are representative of the speech levels found
throughout the entire program.
Infinite mode is most often used in ingest, QC, and postproduction applications where
audio metadata is being authored, the whole piece of content is available, and levels can
usually be controlled and/or adjusted. Infinite mode should be used in automated and
semi‐automated applications.
Using Short-term Measurements
Short‐term measurement mode displays the measured value for only the previous
10‐second period. For example, the first measurement value is for the time interval between
0 and 10 seconds, the next between 1 and 11 seconds, the next between 2 and 12 seconds,
and so forth.
Figure 4‐5 illustrates these measurements.
1 The energy average of two or more quantities expressed on a decibel scale differs from the arithmetic
average of the quantities. The DP570 Pause feature allows the user to properly average measurements (in
dB) across multiple sections of programming.