+ pa_sink_input_assert_ref(i);
+ pa_assert(PA_SINK_INPUT_IS_LINKED(i->state));
+ pa_assert(!v || pa_cvolume_compatible(v, &i->sample_spec));
+
+ if (!v)
+ v = pa_cvolume_reset(&_v, i->sample_spec.channels);
+
+ /* This basically calculates:
+ *
+ * i->relative_volume := v
+ * i->soft_volume := i->relative_volume * i->volume_factor */