Constant libpulse_binding::def::sink_flags::DECIBEL_VOLUME

pub const DECIBEL_VOLUME: SinkFlagSet = capi::PA_SINK_DECIBEL_VOLUME; // 0_x00_000_020u32

Volume can be translated to dB with volume::sw_volume_to_db. This is a dynamic flag and may change at runtime after the sink has initialized.