+class Audio_control_function_value_change : public Audio_item
+{
+public:
+ // Supported control functions.
+ enum Control
+ {
+ BALANCE = 0, PAN_POSITION, EXPRESSION, REVERB_LEVEL, CHORUS_LEVEL,
+ // pseudo value for representing the size of the enum; must be kept last
+ NUM_CONTROLS
+ };
+
+ Audio_control_function_value_change (Control control, Real value);
+
+ // Information about a context property corresponding to a control function
+ // (name, the corresponding enumeration value, and the allowed range for the
+ // value of the context property).
+ struct Context_property
+ {
+ const char *name_;
+ Control control_;
+ Real range_min_;
+ Real range_max_;
+ };
+
+ // Mapping from supported control functions to the corresponding context
+ // properties.
+ static const Context_property context_properties_[];
+
+ Control control_;
+ Real value_;
+};
+
+int moment_to_ticks (Moment);
+Real moment_to_real (Moment);
+Moment remap_grace_duration (Moment);
+