DTS Pro Series - Manual (Page 16)

The purpose of
DIALNORM
is to achieve a consistent level of dialog from one
program or program source to the next. End-users set volume to achieve a
pleasing and intelligible level of dialog. However, dialog level varies considerably
across different program types. For example, in a feature motion picture, dialog
typically averages -27 dBFS LeqA in order to allow sufficient headroom for
explosions and other effects. In contrast, in a news broadcast the announcer’s
voice may average -15 dB, closer to full scale. Various other programs will have
other dialog levels appropriate to their headroom needs. If there is no
compensation, the end-user will have to turn up the feature film, turn down
the news broadcast, etc. With dialog normalization, a
DIALNORM value of
-27 is assigned to the movie, and a value of -15 is assigned to the newscast.
The dialog levels then match on playback and no user adjustment should
be necessary.
For music, which contains no dialog, DIALNORM may be used to set playback
loudness at a level appropriate in the context of other program material,
determined subjectively.
A
DIALNORM
value of -31 results in no
DIALNORM
attenuation.
For broadcast or disc authoring of a feature motion picture, if direct measurement
has not indicated a different level, set the
DIALNORM
value to -27. This has
been widely accepted as typical for features, and THX-certified playback
equipment assumes a value of -27 in aligning levels between the home and the
dubbing stage.
If more than one codec is being used for the same audio track (for example,
on DVD),
DIALNORM
value should be set the same on all codecs for a
given program.
For further information on
DIALNORM
, including typical values for different types
of programs and music, see:
Tomlinson Holman,
5.1 Surround Sound Up and Running.
Boston: Focal Press,
2000. 163-167.
Manager and User Guide – DTS Pro Series Network Encoder for MAC OSX
5. Dialog Normalization
Dialog Normalization is the use of metadata to control playback level. It has no
effect on encoding or decoding. It is an instruction to playback equipment to
adjust the level of all channels, post-decoding.
A single
DIALNORM
value is applied to a given program: level is not adjusted
within a program. There is no compression involved. All channels are affected
equally.
DIALNORM
can only attenuate.
The
DIALNORM
value entered into the encoder is the subjective average dialog
level of the program,
not
the amount of playback attenuation. The subjective
average dialog level is typically approximated by LeqA measurement. The
correspondence between
DIALNORM
value and attenuation is given in the
following table.
DTS Pro Series Network Encoder for MAC OSX – Manager and User Guide
29 28
DIALNORM value Attenuation
(dialogue level, dBFS LeqA) (dB)
-31 0
-30 1
-29 2
-28 3
-27 4
-26 5
-25 6
-24 7
-23 8
-22 9
-21 10
-20 11
-19 12
-18 13
-17 14
-16 15
DIALNORM value Attenuation
(dialogue level, dBFS LeqA) (dB)
-15 16
-14 17
-13 18
-12 19
-11 20
-10 21
-9 22
-8 23
-7 24
-6 25
-5 26
-4 27
-3 28
-2 29
-1 30