Be smarter about thumbnails

lazy_player/thumbnailer.py

@@ -89,8 +89,7 @@ def generate_thumbnail_sync(file_item: FileItem):
         if not success:
             raise RuntimeError("Failed to query duration")
 
-        # Seek to 1/3 of duration
-        seek_pos = duration // 3
+        def get_sample(seek_pos: int) -> bytes:
             pipeline.seek_simple(Gst.Format.TIME, DEFAULT_SEEK_FLAGS, seek_pos)
 
             # Start playing to capture frame
@@ -110,10 +109,17 @@ def generate_thumbnail_sync(file_item: FileItem):
                 raise RuntimeError("Failed to map buffer")
 
             try:
-            thumbnail = bytes(map_info.data)
+                return bytes(map_info.data)
             finally:
                 buffer.unmap(map_info)
 
+        candidates: list[bytes] = []
+
+        for i in range(3):
+            candidates.append(get_sample(duration // 3 - Gst.SECOND + i * Gst.SECOND))
+
+        thumbnail = max(candidates, key=len)
+
         def set_thumbnail():
             file_item.thumbnail.value = thumbnail