+ age_limit: Age restriction for the video, as an integer (years)
+ formats: A list of dictionaries for each format available, it must
+ be ordered from worst to best quality. Potential fields:
+ * url Mandatory. The URL of the video file
+ * ext Will be calculated from url if missing
+ * format A human-readable description of the format
+ ("mp4 container with h264/opus").
+ Calculated from the format_id, width, height.
+ and format_note fields if missing.
+ * format_id A short description of the format
+ ("mp4_h264_opus" or "19")
+ * format_note Additional info about the format
+ ("3D" or "DASH video")
+ * width Width of the video, if known
+ * height Height of the video, if known
+ webpage_url: The url to the video webpage, if given to youtube-dl it
+ should allow to get the same result again. (It will be set
+ by YoutubeDL if it's missing)
+
+ Unless mentioned otherwise, the fields should be Unicode strings.