+ subtitles = {}
+ tracks = video_data.get('tracks')
+ if tracks and isinstance(tracks, list):
+ for track in tracks:
+ if track.get('file') and track.get('kind') == 'captions':
+ subtitles.setdefault(track.get('label') or 'en', []).append({
+ 'url': self._proto_relative_url(track['file'])
+ })
+