DTS DTS Pro Series manual Dialog Normalization

DTS Pro Series Network Encoder for MAC OSX – Manager and User Guide

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.

DIALNORM value	Attenuation	DIALNORM value	Attenuation
(dialogue level, dBFS LeqA)	(dB)	(dialogue level, dBFS LeqA)	(dB)
-31	0	-15	16
-30	1	-14	17
-29	2	-13	18
-28	3	-12	19
-27	4	-11	20
-26	5	-10	21
-25	6	-9	22
-24	7	-8	23
-23	8	-7	24
-22	9	-6	25
-21	10	-5	26
-20	11	-4	27
-19	12	-3	28
-18	13	-2	29
-17	14	-1	30
-16	15

Manager and User Guide – DTS Pro Series Network Encoder for MAC OSX

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.

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