feat!: field ObjectTrackingAnnotation.segment moved into oneof, added track_id

protos/google/cloud/videointelligence/v1p2beta1/video_intelligence.proto

@@ -405,6 +405,22 @@ message ObjectTrackingFrame {
 
 // Annotations corresponding to one tracked object.
 message ObjectTrackingAnnotation {
+  // Different representation of tracking info in non-streaming batch
+  // and streaming modes.
+  oneof track_info {
+    // Non-streaming batch mode ONLY.
+    // Each object track corresponds to one video segment where it appears.
+    VideoSegment segment = 3;
+
+    // Streaming mode ONLY.
+    // In streaming mode, we do not know the end time of a tracked object
+    // before it is completed. Hence, there is no VideoSegment info returned.
+    // Instead, we provide a unique identifiable integer track_id so that
+    // the customers can correlate the results of the ongoing
+    // ObjectTrackAnnotation of the same track_id over time.
+    int64 track_id = 5;
+  }
+
   // Entity to specify the object category that this track is labeled as.
   Entity entity = 1;
 
@@ -413,9 +429,6 @@ message ObjectTrackingAnnotation {
 
   // Information corresponding to all frames where this object track appears.
   repeated ObjectTrackingFrame frames = 2;
-
-  // Each object track corresponds to one video segment where it appears.
-  VideoSegment segment = 3;
 }
 
 // Video annotation feature.