Add duration to the serialized result (#421)

Co-authored-by: Max Tkachenko <[email protected]>

Author: nick-skriabin

src/env/development.js

@@ -64,7 +64,7 @@ import { TimeSeriesSingle } from "../examples/timeseries_single";
  */
 // import { AllTypes } from "../examples/all_types";
 
-const data = RichTextHtml;
+const data = VideoRectangles;
 
 function getData(task) {
   if (task && task.data) {

src/regions/VideoRegion.js

@@ -55,13 +55,16 @@ const Model = types
     },
 
     serialize() {
-      const { framerate, length } = self.object;
+      const { framerate, length: framesCount } = self.object;
+
+      const duration = self.object?.ref?.current?.duration ?? 0;
 
       const value = {
+        framesCount,
+        duration,
         sequence: self.sequence.map((keyframe) => {
           return { ...keyframe, time: keyframe.frame / framerate };
         }),
-        framesCount: length,
       };
 
       if (self.labels?.length) value.labels = self.labels;