7    using MinMax = std::pair<float, float>;
 
    9    enum class METADATA_KEY
 
   16    inline std::string PayloadObject        = 
"OBJECT";
 
   17    inline std::string PayloadContainer     = 
"CONTAINER";
 
   18    inline std::string PayloadSound         = 
"SOUND";
 
   19    inline std::string PayloadBus           = 
"BUS";
 
   20    inline std::string PayloadNamedParam    = 
"NAMED_PARAM";
 
   21    inline std::string PayloadIntParamValue = 
"NAMED_PARAM_VALUE";
 
   22    inline std::string PayloadFloatParam    = 
"FLOAT_PARAM";