Loudness Control

Loudness control parameters.

When utilizing the Dolby encoding engines, it's possible to provide values for dialog normalization, and what loudness modes should be utilized to comply with the supported standards in Dolby's engines.

Parameter

Description

Allowed Values

Default Value

loudness_mode

Specify the content loudness calculation mode for Dolby Media Generator.

1770-1-di – Dolby Dialogue Intelligence™ with ungated loudness measurement with optional speech gating
1770-2 – level gated loudness measurement
1770-2-di – Dolby Dialogue Intelligence™ will level gated loudness measurement with optional speech gating
1770-3
leqA

none

input_speech

Force enable/disable speech detection for Dolby Media Generator.

yes, no

none

audio_normalization

Specify the target loudness for Dolby Media Generator.

-31–0 or 1–100%

none

dialnorm_threshold

Specify the dialnorm threshold for Dolby Media Generator.

One or two comma separated positive float numbers less than 99.9

none

input_dialnorm

Specify the dialnorm value for Dolby Media Generator. Should be used when the input dialnorm is already measured. Can’t be used with audio_normalization option.

-31 - 1

none

adjust_gain_for_dialnorm

Apply gain or attenuation to the audio signal, so that the loudness of the output audio signal is corrected to be equal to the value specified by input metadata.

yes, no

none

clipmode

Specify the clipmode for Dolby Media Generator.

scale, prolimit, hard

none

prolimiter_max_peak

Set the maximum peak sample value allowed by the limiter output. Allowed only for prolimiter clipmode.

-20.0–-0.1

none

speech_threshold

Speech threshold percentage

Integer number between 0 and 100

none

loudnorm_preset

Loudness measurement and correction according to one of the preset standards

manual, atsc_a85, atsc_a85_agile, ebu_r128, freetv_op59, arib_b32

none

peak_reference

Peak reference mode

true_peak, sample_peak

none

correction_mode

Loudness correction mode

pcm_scale, md_update

none

peak_limit_db

Maximum Audio Output Level

Float number with one digit between -12 and -0.1

-0.1

dynrange_line

Line dynamic range control profile

film_standard, film_light, music_standard, music_light, speech

none

dynrange_rf

RF dynamic range control profile

film_standard, film_light, music_standard, music_light, speech

none

ddp_bitstream_mode

Audio bitstream mode

music_and_effects, visually_impaired, hearing_impaired, dialogue, commentary, emergency, voice_over

none

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For audio_normalization parameter

If a negative integer is provided to the audio_normalization parameter, the number will be interpreted as an absolute value in dB. Percentage values (or positive integers) will be interpreted as relative value where 100% is equal to -31db.