* "start_time" - The start time of the chapter in seconds
* "end_time" - The end time of the chapter in seconds
* "title" (optional, string)
+ heatmap: A list of dictionaries, with the following entries:
+ * "start_time" - The start time of the data point in seconds
+ * "end_time" - The end time of the data point in seconds
+ * "value" - The normalized value of the data point (float between 0 and 1)
playable_in_embed: Whether this video is allowed to play in embedded
players on other sites. Can be True (=always allowed),
False (=never allowed), None (=unknown), or a string