audio: add more enums for labeling

modules/audio/proto/audio_common.proto

@@ -24,3 +24,18 @@ enum MovingResult {
   DEPARTING = 2;
   STATIONARY = 3;
 }
+
+enum AudioType {
+  UNKNOWN_TYPE = 0;
+  POLICE = 1;
+  AMBULANCE = 2;
+  FIRETRUCK = 3;
+}
+
+enum AudioDirection {
+  UNKNOWN_DIRECTION = 0;
+  FRONT = 1;
+  LEFT = 2;
+  BACK = 3;
+  RIGHT = 4;
+}

modules/audio/proto/audio_event.proto

@@ -9,5 +9,7 @@ message AudioEvent {
   optional apollo.common.Header header = 1;
   optional int32 id = 2;  // obstacle ID.
   optional apollo.audio.MovingResult moving_result = 3 [default = UNKNOWN];
-  optional bool siren_is_on = 4;
+  optional apollo.audio.AudioType audio_type = 4 [default = UNKNOWN_TYPE];
+  optional bool siren_is_on = 5;
+  optional apollo.audio.AudioDirection audio_direction = 6 [default = UNKNOWN_DIRECTION];
 }