fix(video): add num_copies to write_video_event (#732)

openadapt/record.py

@@ -441,6 +441,7 @@ def write_video_event(
     video_stream: av.stream.Stream,
     video_start_timestamp: float,
     last_pts: int = 0,
+    num_copies: int = 2,
     **kwargs: dict,
 ) -> dict[str, Any]:
     """Write a screen event to the video file and update the performance queue.
@@ -456,22 +457,28 @@ def write_video_event(
         video_start_timestamp (float): The base timestamp from which the video
             recording started.
         last_pts: The last presentation timestamp.
+        num_copies: The number of times to write the frame.
 
     Returns:
         dict containing state.
     """
     screenshot_image = event.data
     screenshot_timestamp = event.timestamp
     force_key_frame = last_pts == 0
-    last_pts = video.write_video_frame(
-        video_container,
-        video_stream,
-        screenshot_image,
-        screenshot_timestamp,
-        video_start_timestamp,
-        last_pts,
-        force_key_frame,
-    )
+    # ensure that the first frame is available (otherwise occasionally it is not)
+    # TODO: why isn't force_key_frame sufficient?
+    if last_pts != 0:
+        num_copies = 1
+    for _ in range(num_copies):
+        last_pts = video.write_video_frame(
+            video_container,
+            video_stream,
+            screenshot_image,
+            screenshot_timestamp,
+            video_start_timestamp,
+            last_pts,
+            force_key_frame,
+        )
     perf_q.put((f"{event.type}(video)", event.timestamp, utils.get_timestamp()))
     return {
         **kwargs,