Down mixing parameters.
When changing the number of output channels from source material, the following settings control how source audio amplitude and positioning will be mixed into the requested output.
| Parameter | Description | Allowed Values | Default Value |
|---|---|---|---|
| downmix_mode | Dolby Encoding Engine downmix mode | pl2, loro, ltrt | pl2 |
| hybrid_downmix | Hybrid downmix | yes, no | none |
| dmix_preference | DMG audio-dmix-preference option | loro, ltrt, pl2, unknown | none |
| dmix_center_level | Sets Lt/Rt and Lo/Ro downmix(5.1-to-stereo) levels for the central channel. | +3.0, +1.5, 0.0, –1.5, –3.0, –4.5, –6.0, and –inf. | –3.0 |
| dmix_center_level_ltrt | Overrides the Lt/Rt downmix level setting for the central channel when <dmix_center_level> is used. | +3.0, +1.5, 0.0, –1.5, –3.0, –4.5, –6.0, and –inf. | –3.0 |
| dmix_center_level_loro | Overrides the Lo/Ro downmix level setting for the central channel when <dmix_center_level> is used. | +3.0, +1.5, 0.0, –1.5, –3.0, –4.5, –6.0, and –inf. | –3.0 |
| dmix_surround_level | Sets Lt/Rt and Lo/Ro downmix(5.1-to-stereo) levels for Ls and Rs channels. | –1.5, –3.0, –4.5, –6.0, and –inf. | –3.0 |
| dmix_surround_level_ltrt | Overrides the Lt/Rt downmix level setting for Ls and Rs channels when <dmix_surround_level> is used. | –1.5, –3.0, –4.5, –6.0, and –inf. | –3.0 |
| dmix_surround_level_loro | Overrides the Lo/Ro downmix level setting for Ls and Rs channels when <dmix_surround_level> is used. | –1.5, –3.0, –4.5, –6.0, and –inf. | –3.0 |
Note
The metadata does not contain downmix coefficients when the encoded audio is stereo.