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 and Dolby Encoding Engine. | -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 |
| 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 |
| input_dialnorm | Specify the dialnorm value for Dolby Media Generator. Set it to copy to preserve dialnorm value from source file. Should be used when the input dialnorm is already measured. Can’t be used with audio_normalization option. | • float number between -31 and -1 • copy | none |
| speech_threshold | Speech threshold percentage | Integer number between 0 and 100 | none |
| peak_reference | Peak reference mode | true_peak, sample_peak | 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 |
| 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 |
| check_peaks | Check the maximum audio output level (peak_limit_db) when the dialnorm threshold (dialnorm_threshold) is specified | yes, no | no |
| 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 |
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.