specified in the URL.
end_time: Time in seconds where the reproduction should end, as
specified in the URL.
+ chapters: A list of dictionaries, with the following entries:
+ * "start_time" - The start time of the chapter in seconds
+ * "end_time" - The end time of the chapter in seconds
+ * "title" (optional, string)
The following fields should only be used when the video belongs to some logical
chapter or section: