Downmix

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.

ParameterDescriptionAllowed ValuesDefault Value
dmix_center_levelSets 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_ltrtOverrides 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_loroOverrides 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_levelSets 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_loroOverrides 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
dmix_preferenceDMG audio-dmix-preference optionloro, ltrt, pl2, unknownnone
downmix_modeDolby Encoding Engine downmix modepl2, loro, ltrtpl2
hybrid_downmixHybrid downmixyes, nonone

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Note

The metadata does not contain downmix coefficients when the encoded audio is stereo.