Force frame calculation from timestamp only, ignore client frame index

app.py

@@ -692,18 +692,23 @@ def process_video_api(
         # Step 2: Apply each annotation
         for i, ann in enumerate(annotations):
             object_id = ann.get("object_id", 1)
-            frame_idx = ann.get("frame", 0)
             timestamp_ms = ann.get("timestamp_ms", None)
+            frame_idx = ann.get("frame", None)
             x = ann.get("x", 0)
             y = ann.get("y", 0)
             label = ann.get("label", "positive")
             
-            # If timestamp is provided and there's an FPS mismatch, recalculate frame index
+            # Calculate frame from timestamp using Space's FPS (more accurate)
             if timestamp_ms is not None and space_fps and space_fps > 0:
-                recalculated_frame = int((timestamp_ms / 1000.0) * space_fps)
-                if recalculated_frame != frame_idx:
-                    print(f"[API] ℹ️  Recalculating frame: Client frame {frame_idx} @ {timestamp_ms}ms → Space frame {recalculated_frame}")
-                    frame_idx = recalculated_frame
+                calculated_frame = int((timestamp_ms / 1000.0) * space_fps)
+                if frame_idx is not None and calculated_frame != frame_idx:
+                    print(f"[API] ✅ Using timestamp: {timestamp_ms}ms → Frame {calculated_frame} (client sent frame {frame_idx})")
+                else:
+                    print(f"[API] ✅ Calculated frame from timestamp: {timestamp_ms}ms → Frame {calculated_frame}")
+                frame_idx = calculated_frame
+            elif frame_idx is None:
+                print(f"[API] ⚠️  Warning: No timestamp or frame provided, using frame 0")
+                frame_idx = 0
             
             print(f"[API] Adding annotation {i+1}/{len(annotations)}: "
                   f"Object {object_id}, Frame {frame_idx}, ({x}, {y}), {label}")